ACM-1 ACM-2

2 Marks
8- List two important functions of admixtures.
1- Define rheology of fresh concrete.. Two important functions of admixtures are:
Ans –Rheology of fresh concrete is the study of how concrete behaves Improve workability of fresh concrete.
under applied forces, particularly its flow and deformation Enhance setting time or control the rate of hardening.
characteristics before setting. It explains how easily concrete can be Admixtures are added to concrete to modify its properties for specific
mixed, transported, placed, and compacted, which is crucial for construction needs.
workability.
9- What is meant by durability of concrete?
2-What is the purpose of slump test? Durability of concrete refers to its ability to withstand weathering,
The slump test is performed to measure the workability or consistency chemical attack, abrasion, and other environmental conditions without
of fresh concrete. losing its strength and serviceability over time.
 Assess Workability – Indicates how easily concrete can be mixed, Durable concrete ensures a longer life span of structures with minimal
placed, and compacted. maintenance.
 Check Uniformity – Helps in detecting variations between
different batches. 10- State two uses of industrial waste in concrete.
 Ensure Quality Control – Ensures that the mix meets design Two uses of industrial waste in concrete are:
requirements at the site. Fly ash is used as a partial replacement for cement to improve
workability and durability.
3-Differentiate between creep and shrinkage. Ground Granulated Blast Furnace Slag (GGBS) enhances strength and
Creep is the gradual deformation of concrete under sustained load over reduces heat of hydration.
time, while shrinkage is the reduction in volume of concrete due to These materials make concrete more sustainable and cost-effective.
moisture loss or chemical changes, even without any external load.
11- What is the effect of temperature on concrete setting?
4-List any two mechanical properties of hardened concrete. High temperature accelerates the setting and hardening of concrete,
Ans - Two Key Mechanical Properties of Hardened Concrete: which may lead to cracks and reduced strength. Low temperature
Compressive Strength- ,Definition: The ability of concrete to withstand delays the setting time and can slow down strength gain, affecting
axial loads that reduce its size. Tensile Strength- , Definition: The early-age performance. Controlling temperature is essential for proper
ability of concrete to resist tension (pulling forces). curing and durability of concrete.

5- What do you mean by water-cement ratio? 12- Define corrosion of reinforcing steel.
Water-Cement Ratio is the ratio of the weight of water to the weight of Corrosion of reinforcing steel is the chemical or electrochemical
cement in a concrete mix. It controls the strength, durability and reaction between steel and its environment, leading to rust formation
workability of concrete. A lower ratio increases strength, while a and loss of cross-sectional area of the steel bars.
higher ratio improves workability but may reduce durability. It weakens the bond between concrete and steel, reducing the
strength and durability of the structure.
6- Define high strength concrete.
High Strength Concrete (HSC) is a type of concrete that has a 13- Write two characteristics of Ferro-cement.
compressive strength greater than 60 MPa (megapascals).It is Two characteristics of Ferro-cement are:
designed for use in high-rise buildings, bridges, and heavy load 1. High tensile strength due to closely spaced wire mesh
structures, offering improved durability and reduced structural size. reinforcement.
7- Mention two examples of lightweight aggregates. 2. Thin sections with excellent crack resistance and impact
Two examples of lightweight aggregates are: resistance.
 Expanded Clay
 Pumice

ACM-3 ACM-4

14- List two types of synthetic fibres used in fibre reinforced concrete. (6MARKS TYPE)
Two types of synthetic fibres used in fibre reinforced concrete are:
 Polypropylene fibres 1- Explain the rheological behavior of fresh concrete.
 Nylon fibres The rheological behavior of fresh concrete refers to how it flows and
deforms under external forces before it sets. Understanding rheology
15- Define fibre reinforced concrete. is essential for ensuring workability, pumpability, and finishability of
Fibre Reinforced Concrete (FRC) is a type of concrete that contains concrete during construction.
dispersed, short fibres (such as steel, glass, or synthetic) uniformly Key Rheological Properties:
mixed within the concrete. These fibres improve tensile strength, 1. Yield Stress:
ductility, and resistance to cracking and impact. o The minimum stress required to initiate flow in fresh
concrete.
16- Mention two advantages of polymers in civil engineering. o Influences how concrete behaves during placement and
Two advantages of polymers in civil engineering are: compaction.
1. Improved durability and chemical resistance of construction 2. Plastic Viscosity:
materials. o Describes the resistance to flow once the concrete starts to
2. Lightweight and easy to mold for complex shapes and deform.
applications. o Affects the ease of pumping and spreading.
3. Thixotropy:
17- What is a sandwich panel? o Time-dependent decrease in viscosity; concrete becomes
A sandwich panel is a composite construction material consisting of more workable when agitated and stiffens when at rest.
two strong outer layers (usually metal or fibre-reinforced plastic) and o Important for self-compacting and shotcrete applications.
a lightweight core (like foam or honeycomb) in-between.It offers high Factors Affecting Rheology:
strength-to-weight ratio, thermal insulation, and soundproofing, 1. Water-Cement Ratio (w/c): Higher w/c improves flow but
commonly used in walls, roofs, and prefabricated structures. reduces strength.
2. Aggregate Size and Shape: Rounded aggregates improve flow;
18- What is the use of adhesives in construction? angular ones increase internal friction.
Adhesives in construction are used to bond materials together such as 3. Use of Admixtures: Superplasticizers reduce yield stress and
concrete, wood, glass, metals, and plastics. They provide uniform improve flowability.
stress distribution, reduce the need for mechanical fasteners, and 4. Temperature: Higher temperatures increase the rate of stiffening.
enhance the aesthetic and structural integrity of joints. Applications:
 Ensuring uniform placement without segregation.
19- Define structural elastomeric bearings.  Designing self-compacting concrete (SCC).
Structural elastomeric bearings are flexible support components made  Improving pumping efficiency and reducing formwork pressure.
of rubber or elastomer (often reinforced with steel plates) used in 2- Describe the mechanical and deformational behaviour of hardened
bridges and buildings. They allow for controlled movement (like concrete.
expansion, contraction, and rotation) and help in transferring loads The mechanical and deformational behaviour of hardened concrete
while reducing vibrations and stresses. describes how it responds to applied loads, including its strength,
stiffness, and deformation characteristics. These properties determine
20- List two applications of moisture barriers in buildings. the structural performance and durability of concrete.
Two applications of moisture barriers in buildings are: Mechanical Behaviour:
1. Preventing water seepage through basement walls and a) Compressive Strength:
foundations.  Most important property of concrete.
2. Protecting roofs and walls from moisture penetration in wet or  Concrete has high compressive strength, usually tested after 28
humid environments. days.
 Influenced by water-cement ratio, curing, and mix design.
 ACM-5 ACM-6

b) Tensile Strength:  Method: Beam specimens are subjected to two-point loading until
 Concrete is weak in tension, typically 1/10th of its compressive failure.
strength.  Standard: IS 516 / ASTM C78
 Cracks easily under tensile stresses, which is why reinforcement  Significance: Important for pavements, slabs, and structures
is used. subjected to bending stresses.
c) Flexural Strength (Modulus of Rupture): Split Tensile Strength Test
 Resistance to bending or flexural loading.  Purpose: Evaluates the indirect tensile strength of concrete.
 Important in pavements and slabs.  Method: A cylindrical specimen is placed horizontally and
d) Elastic Modulus: compressed along its length, causing it to split.
 Measures stiffness of concrete (stress/strain ratio in the elastic  Standard: IS 5816 / ASTM C496
range).  Significance: Helps assess concrete's cracking resistance and
 Higher strength concrete usually has higher modulus of elasticity. supports design decisions for reinforcement.
Deformational Behaviour:
a) Creep: 4- Compare the properties of high strength concrete and normal
 Time-dependent deformation under sustained load. concrete.
 Can affect long-term deflection and structural stability. High Strength Concrete
b) Shrinkage: Property Normal Concrete (NC)
(HSC)
 Volume reduction due to loss of moisture or chemical changes.
Compressive
 Includes drying shrinkage, plastic shrinkage, and autogenous 20–40 MPa Above 60 MPa
Strength
shrinkage.
c) Cracking: Water-Cement
0.45 – 0.6 (higher) 0.25 – 0.4 (lower)
 Occurs due to tensile stresses, thermal changes, drying, or Ratio
structural loads. Very high due to low
Durability Moderate
 Affects durability and aesthetics. permeability
d) Poisson’s Ratio: Good, may need
 Ratio of lateral strain to axial strain under axial loading. Maintained using
Workability adjustment to avoid
 Typically around 0.15 to 0.20 for concrete. superplasticizers
segregation
Shrinkage & Lower, if well-designed and
3- Discuss any three standard tests conducted on hardened concrete. Higher
Creep cured properly
Testing of hardened concrete is essential to evaluate its strength,
durability, and quality after setting. Below are three common standard General structures, High-rise buildings,
Applications
tests: residential buildings bridges, precast elements
Compressive Strength Test 5-Explain the properties and uses of high-density concrete.
 Purpose: To determine the maximum load concrete can withstand Ans- Properties:
under compression. 1. High Density: Typically ranges from 3000 to 5800 kg/m³, much
 Method: Cube or cylinder specimens (e.g., 150 mm cubes) are higher than normal concrete (~2400 kg/m³), due to the use of
tested in a compression testing machine after 7, 14, or 28 days of heavy aggregates like barite, magnetite, or hematite.
curing. 2. Radiation Shielding: Excellent at attenuating gamma rays and X-
 Standard: IS 516 / ASTM C39 rays, making it suitable for radiation protection.
 Significance: It’s the most widely used test for quality control of 3. High Strength: Offers high compressive strength, suitable for
concrete. structural and protective applications.
Flexural Strength Test 4. Durability: Good resistance to weathering and chemical attack
 Purpose: Measures the bending or tensile strength of concrete when properly mixed and cured.
(modulus of rupture). 5. Low Workability: Heavier aggregates may reduce workability,
requiring admixtures or vibration during placement.

ACM-7 ACM-8

Uses: 1. Workability (Fresh Concrete)

1. Nuclear Power Plants: Used in shielding walls and containment  Fly ash particles are spherical and fine, acting like tiny ball
structures to protect against radiation. bearings.
2. Medical Facilities: In radiology rooms and linear accelerator vaults  This enhances workability and makes concrete easier to place and
to block harmful rays. finish without increasing water content.
3. Industrial Radiography: Shields workers from exposure during 2. Heat of Hydration
testing processes.  Fly ash reacts more slowly than cement.
4. Ballast and Counterweights: In offshore structures or heavy  It reduces the heat of hydration, which minimizes thermal
machinery where mass is required in limited space. cracking, especially useful in mass concrete structures like dams.
3. Strength Development
6-Describe the role and classification of admixtures in concrete.  Early strength may be lower due to slower pozzolanic reaction.
Ans- Role of Admixtures:  However, long-term strength (28 days and beyond) is improved
1. Improve Workability: Admixtures like plasticizers and as fly ash continues to react with calcium hydroxide forming
superplasticizers enhance the flow of concrete without increasing additional C–S–H gel.
water content. 4. Durability
2. Accelerate or Retard Setting Time: Accelerators speed up setting  Fly ash improves resistance to sulfate attack, alkali-silica reaction
for cold weather concreting, while retarders delay setting for hot (ASR), and chloride penetration.
climates or large pours.  It refines the pore structure and makes concrete denser and less
3. Enhance Durability and Strength: Certain admixtures improve permeable, enhancing durability.
long-term performance by reducing permeability or shrinkage. 5. Environmental & Economic Benefits
4. Control Air Content: Air-entraining agents introduce tiny air  Reduces cement consumption, lowering CO₂ emissions.
bubbles, increasing freeze-thaw resistance.  Makes concrete more cost-effective.
Classification of Admixtures : 8-Discuss the behavior of concrete in hot weather concreting.
1. Chemical Admixtures: Ans- 1. Rapid Loss of Workability
o Plasticizers and Superplasticizers: Improve workability and  High temperature accelerates evaporation of water, causing rapid
reduce water-cement ratio. slump loss.
o Accelerators: Speed up early strength gain (e.g., calcium  Results in stiff and unworkable mix, making compaction and
chloride). finishing difficult.
o Retarders: Slow down setting time (e.g., sugar-based 2. Increased Risk of Plastic Shrinkage Cracking
compounds).  Rapid surface drying causes plastic shrinkage cracks before the
o Air-Entraining Agents: Increase resistance to freezing and concrete sets.
thawing.  Especially occurs in slabs and pavements.
o Waterproofing Admixtures: Reduce permeability. 3. Accelerated Setting Time
2. Mineral Admixtures:  Heat speeds up hydration reactions, reducing setting time.
o Pozzolanic Materials: Fly ash, silica fume, and slag improve  Leaves less time for placing, compaction, and finishing.
strength and durability by reacting with calcium hydroxide. 4. Reduction in Strength
o Fillers: Such as limestone powder, which may improve  Due to faster hydration and possible water loss, the water-cement
workability and finish. ratio may increase, reducing strength.
 Inadequate curing under hot conditions can further reduce long-
7-Explain how fly ash influences concrete properties. term strength.
5. Increased Thermal Cracking
Ans- Fly ash, a by-product of coal combustion in thermal power plants,  Large temperature differences between the surface and core of
is widely used as a pozzolanic material in concrete. When added to mass concrete may cause thermal stresses and cracking.
concrete, it significantly influences its fresh, hardened, and durability 6. Durability Problems: Rapid drying can lead to poor curing, resulting
properties: in porous and weak surface layers, reducing durability.
 ACM-9 ACM-10

9-Explain corrosion of reinforcing steel and its prevention. o Repair Works:Ideal for jacketing columns, retrofitting structures,
Corrosion is the chemical or electrochemical deterioration of steel in and patch repairs.
concrete due to reaction with environmental agents, primarily o Prefabricated Elements:Manhole covers, bench slabs, and railings.
moisture, oxygen, and chlorides. It converts steel into rust (iron o Housing:Low-cost modular housing panels, walls, and roofs in rural
oxide), which occupies more volume and causes cracking, spalling, and areas.
loss of bond strength in concrete.
Prevention Methods 11-Write short notes on polypropylene and glass fibres in FRC.
1. Good Quality Concrete: Polypropylene Fibres in FRC
o Low water-cement ratio (≤ 0.45) to reduce permeability. Description:Polypropylene fibres are synthetic polymer fibres made
o Adequate compaction and curing. from polypropylene, a thermoplastic material.
2. Proper Cover Depth: Properties:
o Sufficient concrete cover protects steel from external  Low density, chemically inert, and resistant to corrosion.
environment.  High tensile strength and good crack resistance.
3. Use of Mineral Admixtures:  Do not bond chemically with cement, but provide mechanical
o Fly ash, GGBS, silica fume improve concrete densification and anchorage.
resistance. Functions in Concrete:
4. Corrosion-Resistant Steel:  Reduce plastic shrinkage cracking and bleeding in early-age
o Use of epoxy-coated, stainless steel, or galvanized bars. concrete.
5. Cathodic Protection:  Improve impact resistance and toughness.
o Uses sacrificial anodes or impressed current to prevent  Commonly used in floors, overlays, precast elements, etc.
corrosion. Glass Fibres in FRC
6. Waterproofing and Sealants: Description:
o Surface coatings prevent ingress of water and chlorides. Glass fibres are inorganic fibres made from fine glass filaments,
typically used in the form of alkali-resistant (AR) glass to withstand
10-Describe the properties of ferro-cement and its civil engineering cement alkalinity.
uses. Properties:
Properties of Ferrocement  High tensile strength and modulus of elasticity.
o High Tensile Strength: Due to multiple layers of mesh reinforcement,  Good fire resistance and dimensional stability.
it has better tensile strength than plain concrete. Functions in Concrete:
o High Crack Resistance: The fine mesh controls crack width and  Improve tensile strength, flexural strength, and surface hardness.
distributes stress evenly.  Enhance crack resistance and durability.
o Thin Section Construction :Allows lightweight and slender sections  Widely used in GRC panels, façade cladding, thin shells, etc.
(10–50 mm thick).
o Durability :Dense mortar matrix and uniform distribution of 12-Explain the mechanical behavior of fibre reinforced concrete.
reinforcement improve resistance to weathering and corrosion. Fibre Reinforced Concrete (FRC) is a composite material where
o Formability and Workability :Can be molded into any shape, making discrete fibres (steel, glass, synthetic, or natural) are uniformly
it ideal for complex or curved structures. distributed within the concrete matrix. These fibres significantly
o Economical :Requires less formwork and skilled labor; cost-effective enhance the mechanical performance of concrete.
for small-scale applications. 1. Improved Tensile Strength
Civil Engineering Uses  Fibres bridge micro-cracks and resist crack widening.
o Water Structures:Water tanks, boats, pipes, and canal linings due to  Enhances tensile load-carrying capacity of concrete, which is
waterproof nature. naturally weak in tension.
o Roofing and Cladding:Used for roof shells, domes, wall panels, and 2. Increased Flexural Strength
facades.  Improves modulus of rupture and post-crack load-bearing
capacity.

ACM-11 ACM-12

3. Enhanced Toughness and Energy Absorption Behavior of Sandwich Panels

 FRC is more ductile and shows better toughness (area under the a) High Strength-to-Weight Ratio :The core provides thickness and
stress-strain curve). stiffness without adding much weight.
 Can absorb more energy before failure – useful in impact- or b) Excellent Thermal and Acoustic Insulation :The core material has
blast-resistant structures. low thermal conductivity, making panels ideal for energy-efficient
4. Crack Control and Ductility buildings.
 Fibres control the formation and propagation of cracks. C) Ease of Installation :Prefabricated and lightweight, leading to fast
5. Improved Fatigue and Impact Resistance and cost-effective construction.
 Fibres improve fatigue life under repeated loading. D) Durability and Weather Resistance :Outer skins are resistant to
6. Shear Strength Enhancement weather, corrosion, and impact, increasing panel life.
 In some cases, fibres improve shear strength, reducing the need 15- Describe the structural modelling of fibre reinforced plastics.
for shear reinforcement in thin sections. Fibre Reinforced Plastics (FRP) are composite materials made of fibres
13-Discuss the advantages and limitations of polymers in construction. (glass, carbon,ramid) embedded in a polymer matrix (epoxy,
Advantages of Polymers in Construction polyester, or vinyl ester).Structuralmodeling of FRP is essential to
o Polymers have a high strength-to-weight ratio, making them ideal predict its behavior in load-bearing applications.
for lightweight structures and components. Key Aspects of Structural Modeling
o Unlike steel or concrete, polymers are resistant to moisture, a) Anisotropic Behavior
chemicals, and corrosion, improving longevity.  FRPs are anisotropic, meaning their properties differ in different
o Can be molded into complex shapes, allowing for innovative designs directions.
and prefabricated elements. b) Constituent-Based Approach
o Excellent insulating properties, useful in electrical and thermal  Modeling considers both fibre and matrix properties.
applications (e.g., wiring insulation, cladding). Types of Modeling Techniques
o Preformed polymer products are easy to install, with minimal i) Micromechanical Modeling
maintenance requirements.  Used to predict elastic properties from the properties and volume
Limitations of Polymers in Construction fraction of fibres and matrix.
o Most polymers are flammable and may emit toxic gases when ii) Laminate Theory (Classical Laminate Theory – CLT)
burned, requiring fireproofing measures.  Models multilayered FRP laminates with different fibre orientations.
o Not suitable for primary load-bearing structures due to low modulus  Calculates in-plane and bending stiffness using stacking sequence
of elasticity. and ply properties.
o Properties can degrade at high temperatures or under UV exposure iii) Finite Element Modeling (FEM)
unless stabilized.  Used for complex structures and loading conditions.
o Many polymers are non-biodegradable and petroleum-based, raising  Simulates stress distribution, failure modes, and deformation
sustainability issues. behaviour.
o Polymers may undergo creep (long-term deformation) under 16- Explain the architectural benefits of composites.
sustained loads, especially at high temperatures. Composites are engineered materials made by combining two or more
14-Explain the concept and behavior of sandwich panels in buildings. distinct materials to form a product with enhanced properties. In
Concept of Sandwich Panels architecture, composites like fibre-reinforced plastics (FRP), glass-
Sandwich panels are composite structural elements consisting of three reinforced concrete (GRC), and carbon-fibre composites offer several
layers: functional and aesthetic advantages.
 Two outer face sheets (usually made of steel, aluminum, or fiber- Design Flexibility
reinforced polymers)  Composites can be molded into complex shapes, curves, and
 One lightweight core (made of materials like polyurethane foamor custom profiles.
mineral wool) Lightweight Structures
These layers are bonded together to form a single unit with high  High strength-to-weight ratio allows large spans and cantilevers
structural efficiency. with reduced self-weight.
 ACM-13 ACM-14

High Durability and Low Maintenance 3. Moisture Resistance

 Resistant to corrosion, weathering, UV radiation, and chemicals.  Many polymer foams are hydrophobic, resisting moisture
 Ideal for harsh environments like marine, industrial, and coastal absorption.
areas.  Prevents mold growth and thermal performance degradation in
Thermal and Acoustic Insulation humid environments.
 Many composites provide good insulation properties, enhancing 4. Acoustic Insulation
indoor comfort.  Closed-cell and open-cell foams reduce sound transmission and
 Helps in achieving energy-efficient and sustainable buildings. dampen vibrations.
Fast Construction and Prefabrication  Useful in partition walls, ceilings, and soundproofing panels.
 Composite panels and elements can be factory-made and 5. Applications in Buildings
assembled on-site, reducing construction time.  Roof insulation (PU foam spray)
Aesthetic Appeal  Wall cladding and cavity filling (EPS boards)
 Composites can mimic natural materials like stone, wood, or 6. Sustainability and Fire Safety
metal, while offering better performance.  Some foams are recyclable or made with eco-friendly blowing
 Available in various textures, finishes, and colors, enhancing agents.
architectural expression.  Must include fire retardants to reduce flammability and toxic fume
17- Differentiate between adhesives and sealants with examples. risk.
Aspect Adhesives Sealants 19- What are polymer concrete composites? Explain with examples.
Polymer Concrete Composites are a class of advanced construction
Used to bond/join two or
Used to seal gaps or joints materials in which polymers are used as binders (either partially or
Function more surfaces
to prevent leakage fully replacing cement) to bind the aggregate particles. These
permanently
composites exhibit enhanced strength, durability, and chemical
High mechanical strength Lower strength, designed resistance compared to traditional cement concrete.
Bond Strength
(strong bonding) for flexibility and sealing Types of Polymer Concrete
Generally rigid or semi- Highly flexible to a) Polymer-Impregnated Concrete (PIC),b) Polymer-Modified Concrete
Flexibility
rigid after curing accommodate movement (PMC),c) Polymer Concrete (PC)
Joining materials like Sealing joints in concrete, Application Example
Primary Use
wood, metal, plastics glass, tiles, plumbing etc. Epoxy polymer concrete used in chemical
Industrial flooring
Silicone sealant, Acrylic factories.
Epoxy resin, Fevicol,
Examples sealant, Polyurethane PMC used for repairing bridge decks and
Araldite, Super glue Repair and patching
sealant pavements.
Typical Furniture making, Window frames, expansion PIC applied in wastewater infrastructure
Applications automotive, packaging joints, bathrooms, roofing Sewer linings
for durability.
18- Describe the role of polymer foams in insulation. PC used in making drains, manhole covers,
Polymer foams are lightweight materials with cellular structures that Precast elements
and countertops.
trap air or gas within a polymer matrix. They play a significant role in
Polymer concrete used for corrosion-prone
thermal and acoustic insulation in buildings and infrastructure. Marine structures
environments.
1. Excellent Thermal Insulation
 Trapped air/gas pockets in polymer foams are poor conductors of
heat.
 Reduce heat transfer by conduction, convection, and radiation.
2. Lightweight and Easy to Handle
 Very lightweight compared to other insulating materials.
 Easy to cut, shape, and install in walls, roofs, ceilings, and floors.

ACM-15 ACM-16

20- Explain the function of elastomeric bearings in structures. 8MARKS

Ans :Elastomeric bearings are flexible support devices used in
structures, especially bridges and buildings, to accommodate 1- Explain the microstructure of hardened concrete and its impact on
movements and transfer loads between structural elements. strength.
They are typically made from layers of natural or synthetic rubber Ans: Hardened concrete is a heterogeneous composite material
(elastomer) bonded with steel plates for strength. consisting of hydrated cement paste, aggregates, and air voids. Its
Primary Functions microstructure refers to the internal structure formed after hydration
a) Load Transfer of cement, which directly influences its strength, durability, and
 Transfer vertical loads from the superstructure (like bridge decks) performance.
to the substructure (like piers and abutments). Key Components of Microstructure
 Distribute loads evenly, reducing stress concentrations. a) Hydrated Cement Paste (HCP)
b) Accommodate Movements  Main binding phase formed by the reaction between cement and
 Allow for thermal expansion and contraction, creep, and shrinkage water.
of the structure.  Composed of:
 Prevent cracking or damage by absorbing deformations. o Calcium Silicate Hydrate (C–S–H) – the primary strength-giving
c) Allow Rotation and Flexibility phase.
 Permit rotational movements due to traffic loads or structural o Calcium Hydroxide (Ca(OH)₂) – crystalline and weaker.
deflection. o Ettringite and Monosulfate – from sulfate reactions.
 Maintain contact and stability between connected parts. b) Aggregates
d) Vibration and Shock Absorption  Inert fillers that provide volume stability and strength.
 Act as dampers that absorb vibrations, shocks, and seismic forces,  Interface between cement paste and aggregate is critical.
protecting the structure and its users. c) Interfacial Transition Zone (ITZ)
 Thin layer (~10–50 µm) between aggregates and cement paste.
 Generally more porous and weaker than the bulk paste.
 ITZ is often the weakest link, affecting crack initiation and
propagation.
d) Capillary Pores and Gel Pores
 Capillary pores: Leftover water-filled spaces that did not hydrate –
major influence on permeability and strength.
e) Microcracks
 Can form due to shrinkage, loading, thermal changes, or poor
curing.
 Act as stress concentrators, leading to reduced strength.
Impact on Strength
Microstructural Feature Impact on Strength
C–S–H Content Higher C–S–H = higher compressive strength
Capillary Porosity More porosity = weaker concrete
ITZ Quality Dense ITZ = better bonding with aggregates
Water-Cement Ratio Lower w/c = denser microstructure, higher
(w/c) strength
Curing and Age Proper curing = more hydration, better strength
More microcracks = reduced tensile and flexural
Microcrack Density
strength
 ACM-17 ACM-18

2 -Discuss in detail the shrinkage and creep behavior in concrete and  Based on exposure: ensure it meets durability(max 0.45 for severe
its control. exposure)
Ans: Shrinkage in Concrete 3. Selection of Water Content (1 Mark)As per IS 10262:
Types of Shrinkage:  For 20 mm aggregates, water content ≈ 186 kg/m³ (adjusted for
Plastic Shrinkage- Occurs in fresh concrete due to rapid moisture workability, admixtures)
evaporation.Leads to surface cracking within few hours after placing. 4. Calculation of Cement Content
Drying Shrinkage - Due to loss of moisture from hardened concrete to Cementcontent=Watercontent = 186 / 0.4 = 465kg/ m3
the environment.Most common type; occurs over weeks to years. W/cratio
Autogenous Shrinkage - Caused by self-desiccation during hydration in 5. Selection of Aggregates and Proportions
low water-cement ratio concrete.  Coarse Aggregate (CA) and Fine Aggregate (FA) are selected as per
Thermal Shrinkage - Occurs when concrete cools down after the heat grading zone and IS tables
of hydration.  Volumetric proportion of CA and FA based on nominal max size of
Creep in Concrete aggregates and workability
Creep is the gradual, time-dependent increase in strain under 6. Mix Calculations (Proportioning)
sustained load.  Total volume = 1 m³
Occurs mostly in the cement paste, especially in moist conditions.  Calculate volume of cement, water, admixtures, and then
Significant in columns, prestressed members, and long-span beams. aggregates using specific gravities
Control Measures  Adjust volumes using air content (typically 2% entrapped air for 20
a) For Shrinkage: mm aggregate)
 Use low water-cement ratio 7. Admixture Dosage
 Proper curing to retain moisture and promote hydration  Superplasticizers often used to reduce water and maintain
 Use shrinkage-reducing admixtures workability
 Provide joints to accommodate movement  Dosage based on manufacturer’s specification (typically 0.5–2%
 Use of fibres (e.g., polypropylene) to control cracking by weight of cement)
b) For Creep: 8. Trial Mix and Adjustment
 Use high-strength, well-cured concrete Prepare trial mixes to verify strength, workability, and durability
 Delay loading until concrete gains sufficient strength  Adjust mix if actual properties deviate from design
 Use mineral admixtures (e.g., fly ash, silica fume) to reduce paste Final Result :
content A typical M40 concrete mix (by weight ratio):
 Design with larger cross sections to reduce stress levels Cement :FA : CA = 1 :1.6 : 2.8,
 Prestressing helps to reduce long-term creep deflection Water-cement ratio = 0.40,
3-Describe the mix design procedure for M40 grade concrete. Water = 186 kg/m³,
Ans: The mix design for M40 grade concrete (characteristic Cement = 465 kg/m³
compressive strength of 40 MPa) is carried out as per IS 10262:2019
and IS 456:2000. The procedure involves the following steps: 4-Write in detail about the physical and mechanical properties of light
1. Target Mean Strength Calculation weight concrete.
To ensure the concrete achieves M40 strength, a target mean strength
is calculated:fck=fck_target=fck+1.65×S Ans :Lightweight concrete (LWC) is a type of concrete that contains
Where:fck = characteristic strength (40 MPa) lightweight aggregates or air entrainment to reduce its density while
S = standard deviation (assumed as 5 MPa for M40 as per IS 10262) maintaining adequate strength and durability. The key physical and
fck_target=40+1.65×5=48.25 MPa mechanical properties are :
2. Selection of Water-Cement Ratio 1. Density (Unit Weight)
Based on durability (IS 456:2000) and strength requirements, the w/c  Range: 800 to 2000 kg/m³
ratio is selected. For M40:  Comparison: Significantly lower than normal concrete (2300–
 Based on strength: w/c ≈ 0.38–0.40 2500 kg/m³)

ACM-19 ACM-20

2. Compressive Strength 4. Retarding Admixtures ,Effect on Workability:

 Range: Typically 7 to 40 MPa (can go higher with high-  Delay the setting time of concrete, allowing longer workability time
performance lightweight aggregates) 5. Accelerating Admixtures ,Effect on Workability:
 Strength vs Density: As density increases, compressive strength  May reduce workability slightly due to faster setting
also tends to increase  Increase early strength development but reduce time available for
3. Thermal Insulation placing and compaction
 Superior thermal performance due to air voids and porous 6- Pozzolanic Admixtures (e.g., Fly Ash, Silica Fume, GGBS),,Effect on
aggregates Workability:
 Result: Better energy efficiency in buildings, reduces HVAC load  Can improve workability due to spherical particle shape (fly ash)
4. Workability 7. Viscosity Modifying Admixtures (VMAs), Effect on Workability:
 Generally lower workability due to rough surface texture and  Improve cohesion of highly flowable mixes
angular shape of lightweight aggregates  Reduce segregation and bleeding
 Improvement: Superplasticizers or air entraining agents are used
to enhance workability 7- Describe in detail how blast furnace slag and silica fume
5. Modulus of Elasticity affectconcrete properties.
 Lower than normal concrete Ans:
 Typical value: 10 to 22 GPa (compared to 25–35 GPa for normal 1. Ground Granulated Blast Furnace Slag (GGBS)
concrete) Effects on Concrete Properties:
6. Tensile and Flexural Strength a) Workability:
 Lower than normal concrete but proportional to compressive  Improved workability due to smooth, glassy particles
strength  Reduces water demand and bleeding
 Tensile strength: ~7–10% of compressive strength b) Setting Time:
 Flexural strength: ~10–15% of compressive strength  Increases initial setting time (beneficial in hot weather)
7. Durability  May delay finishing operations in cold climates
 Depends on quality of aggregates and mix design c) Strength Development:
 Lightweight concrete is generally more resistant to fire and  Slow early strength gain but higher long-term strength (28 to 90
chemical attack days)
8. Shrinkage and Creep  Useful in mass concrete (e.g., dams) due to low heat of hydration
 Shrinkage: Higher than normal concrete due to higher water d) Durability:
content and porosity  Excellent sulfate resistance
 Creep: Also higher, especially in low-strength mixes  Reduces permeability → better resistance to chloride ingress
5- Explain various types of admixtures and their effect on workability.  Improves resistance to alkali-silica reaction (ASR)
Ans: e) Color:
1. Water-Reducing Admixtures (Plasticizers), Effect on Workability:  Produces lighter-colored concrete (beneficial for aesthetic
 Increase workability without increasing water content, or applications)
 Allow reduction of water while maintaining the same workability 2. Silica Fume
2. High-Range Water Reducers (Superplasticizers), Effect on Effects on Concrete Properties:
Workability: a) Workability:
 Significantly increase workability (slump can rise from 75 mm to  Reduces workability due to high surface area
200 mm or more)  Needs superplasticizers to maintain workability
 Useful for high-strength &flowable concrete, or heavily reinforced  Improves cohesiveness, reducing segregation and bleeding
sections. b) Strength Development:
3. Air-Entraining Admixtures ,Effect on Workability:  Significantly increases strength, especially compressive and
 Improve workability by introducing tiny air bubbles into the mix flexural
 Make concrete more cohesive, reducing segregation and bleeding  Used in high-strength concrete (>60 MPa)
 ACM-21 ACM-22

c) Durability: Diagram 3
 Drastically reduces permeability [ Heater ]
 Enhances resistance to chemical attack, sulfate attack, and ↓
chloride ingress [ Thawed Subgrade ]
d) Microstructure: ↓
 Refines pore structure by producing additional C-S-H gel [ Fresh Concrete Slab ]
 Densifies the interfacial transition zone (ITZ) between aggregate
and cement paste. 9- Discuss the various forms of concrete corrosion and their remedies.
8- Explain with diagrams the techniques used for concreting in cold
weather. Ans:
Ans: Techniques Used : 1. Corrosion of Steel Reinforcement (Electrochemical):
1. Heating of Materials (Aggregate & Water): Cause: Moisture and oxygen penetrate through cracks or porous
Purpose: Prevent freezing and maintain concrete temperature above concrete. In presence of chlorides or carbonation, the passive oxide
10°C. layer on steel breaks down, leading to rust.
Method:Water: Heated using coils or steam before mixing. Remedies:Use low-permeability concrete (dense mix, low water-
Aggregates: Heated in bins or with steam. cement ratio).
Diagram-1 Provide adequate cover over reinforcement.
Heat Source
↑ 2. Carbonation Corrosion:
[ Water Tank ] [ Aggregate Bin ] Cause: CO₂ from air reacts with calcium hydroxide in concrete to form
↓↓ calcium carbonate, reducing pH and depassivating steel.
Mixing Drum → Warm Concrete Remedies:Increase concrete cover depth.
2. Use of Accelerators and Air-Entraining Agents: Use pozzolanic materials (fly ash, silica fume) to reduce porosity.
 Accelerators (e.g., CaCl₂): Speed up setting time and early
3. Chloride-Induced Corrosion:
strength gain.
Cause: Chloride ions (from deicing salts or seawater) penetrate
 Air-Entraining Agents: Improve freeze-thaw resistance.
3. Insulated Formwork and Coverings: concrete and disrupt the protective film on steel.
 Purpose: Retain heat of hydration and protect against freezing. Remedies:Use chloride-free admixtures.
 Method: Use of insulated blankets, foams, or heated enclosures. Use supplementary cementitious materials (SCMs) like GGBS to bind
Diagram-2 chlorides.
4- Sulphate Attack:
[ Insulating Blanket ]
↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓ Cause: Sulphates from soil or groundwater react with tricalcium
┌──────────────────┐ aluminate (C₃A) in cement forming expansive compounds (ettringite).
│ Fresh Concrete │ ← Wooden/Steel Formwork Remedies:Use sulphate-resisting cement (SRC).Ensure good drainage
└──────────────────┘ and waterproofing.
↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑ 5. Alkali-Aggregate Reaction (AAR):
Heat Retained
Cause: Reactive silica in aggregates reacts with alkalis (Na₂O, K₂O) in
4. Extended Curing Period:
 Concrete gains strength slowly in cold.
cement in presence of moisture.
 Curing is done using warm water, steam, or insulating blankets for a Remedies:Use non-reactive aggregates.
longer duration.
5- Avoidance of Frozen Subgrade:
 Frozen ground expands → cracks concrete
 Subgrade must be thawed using heaters before placing concrete.

ACM-23 ACM-24

10- Compare the characteristics and uses of ferrocement vs RCC. o Improves abrasion resistance and toughness.
Ans: 5. Natural Fibres (Coir, Jute, Sisal, Hemp):
Comparison Table: Effects on Performance:
RCC (Reinforced Cement o Biodegradable but can improve crack resistance temporarily.
Aspect Ferrocement o Sustainable, but lower strength and durability than
Concrete)
synthetics.
Concrete (cement + sand +
Cement mortar + closely 6. Carbon Fibres (High-Performance):
Composition aggregates) + steel bars
spaced wire mesh Effects on Performance:
o Very high tensile strength and stiffness.
Thicker sections as per o Lightweight, corrosion-resistant but expensive.
Thickness Thin sections (10–50 mm) structural design 12 Explain the workability tests conducted on fibre reinforced concrete.
Ans: Workability Tests for FRC:
High compressive and tensile 1. Slump Test (IS 1199):
High tensile strength and
Strength strength Purpose: Measures the consistency or flow of fresh concrete.
crack resistance
Procedure: Standard slump cone is filled with fresh FRC in 3 layers,
Heavy due to aggregates and each compacted. Cone is lifted, and the slump (vertical drop) is
Weight Lightweight measured. Observation in FRC:
bulk
o Lower slump than plain concrete due to fibre interlocking.
Requires shuttering, mixing,
Labor-intensive, minimal o Slump may be irregular (shear or collapse), not always accurate for
Construction compaction
formwork needed FRC.
2. Vee Bee Consistometer Test:
Water tanks, boats, Beams, slabs, columns,  Purpose: Suitable for low workability concrete.
Typical Uses
panels, repair works bridges, foundations  Procedure: Concrete is placed in a slump cone within a cylindrical
11- Describe the types of fibres used in concrete and their effects on container. After lifting the cone, vibration is applied, and time taken
performance. for concrete to fully remould is measured in seconds.
Ans:  Observation:
Types of Fibres Used in Concrete: o Longer remoulding time with increasing fibre content.
1. Steel Fibres: o Indicates resistance to flow due to fibre network.
Effects on Performance: 3. Compaction Factor Test:
o Increases tensile strength and impact resistance.  Purpose: Measures the degree of compaction under its own weight.
o Controls crack propagation.  Procedure: Concrete is allowed to fall through two hoppers into a
o Improves ductility and load-carrying capacity. cylinder; weight of partially compacted vs fully compacted concrete
2. Glass Fibres: is used to compute the compaction factor.
Effects on Performance:  Observation:
o Enhances surface finish and resistance to weathering. o FRC shows lower compaction factor, indicating reduced flowability.
o Improves tensile and flexural strength. 4. Flow Table Test (for mortar-rich or self-compacting FRC):
o Reduces micro-cracking.  Used especially for fibre mortar or polymer-modified FRC.
3. Polypropylene (PP) Fibres:  Measures horizontal flow of concrete on a shaking table.
Effects on Performance:  Indicates plasticity and cohesiveness of fibre-reinforced mixes.
o Excellent plastic shrinkage crack control. Effect of Fibres on Workability:
o Improves impact resistance and freeze-thaw durability.  Decreased workability due to fibre entanglement and surface area.
o Non-corrosive and chemically inert.  High fibre volume fractions (typically >1.5%) may lead to balling
4. Nylon Fibres: and segregation.
Effects on Performance:  Use of superplasticizers helps improve workability without
o Controls plastic shrinkage and thermal cracking. increasing water content.
 ACM-25 ACM-26

12- Write a detailed note on fibre reinforced plastics in civil Engg.  Cold storage panels (thermal insulation).
Ans: Fibre Reinforced Plastics (FRP) are composite materials made of  Bridge decks and pedestrian walkways.
strong fibres (like glass, carbon, or aramid) embedded in a polymer  Aircraft and vehicle body panels (lightweight design).
matrix (such as epoxy or polyester resin). They are widely used in civil 🔸 Advantages:
engineering due to their light weight, high strength, and corrosion  High strength-to-weight ratio.
resistance.  Good thermal/acoustic insulation.
Components:  Fast and easy installation.
1. Fibres: Provide strength and stiffness. 14-Explain how adhesives and sealants contribute to composite
o Types: Glass (GFRP), Carbon (CFRP), Aramid (AFRP) performance.
2. Polymer Matrix: Binds fibres and transfers load. Adhesives:
o Common resins: Epoxy, Vinyl ester, Polyester  Bond dissimilar materials (e.g., metal to polymer).
Key Properties:  Provide load transfer in composite structures.
 High strength-to-weight ratio  Distribute stresses uniformly → reduced stress concentrations.
 Excellent corrosion resistance  Improve fatigue and vibration resistance.
 Non-magnetic and non-conductive 🔸 Sealants:
 Durable and low maintenance  Prevent moisture, air, and chemical ingress.
Applications in Civil Engineering:  Maintain durability and weatherproofing.
 Structural strengthening of beams, columns, and slabs (wrapping  Used in joints, gaps, and façade panels.
with FRP sheets) 🔸 Contribution to Performance:
 FRP rebars as corrosion-resistant reinforcement  Enhance structural integrity.
 Bridge decks, railings, and panels  Prevent corrosion and degradation at joints.
Advantages:  Allow thermal movement without cracking.
 Lightweight and easy to install  Reduce weight compared to mechanical fasteners
 Resistant to chemicals and moisture 15- Describe different types of structural elastomeric bearings and
 Long service life with minimal upkeep their behavior.
Limitations: Ans: Structural elastomeric bearings are flexible supports used in
 Higher cost compared to traditional materials bridges and buildings to allow controlled movement and rotation.
 Low fire resistance
🔸 Types:
 May show brittle failure without warning
1. Plain Elastomeric Bearing Pads:
o Made of natural or neoprene rubber.
13-Discuss the modelling and applications of sandwich panels in o Allow small displacements and rotations.
structures. 2. Laminated Elastomeric Bearings:
Ans: Sandwich panels are three-layered structural elements composed o Layers of rubber and steel plates bonded together.
of two strong, stiff outer layers (face sheets) bonded to a lightweight o Withstand vertical loads and allow horizontal movement.
core. 3. Pot Bearings:
🔸Modeling: o Rubber confined in a steel pot.
 Treated as composite beams or plates. o Suitable for high loads and rotations.
 Outer layers resist bending and tensile/compressive stresses. 4. Spherical Bearings:
 Core resists shear forces and provides thermal/acoustic o Allow large rotational movement.
insulation. o Used in curved bridges and complex structures.
 Analyzed using finite element methods (FEM) or classical laminate
🔸Behavior:
theory.  Accommodate thermal expansion, seismic, and traffic loads.
🔸 Applications:  Provide vibration isolation.
 Walls, floors, and roofs in prefabricated buildings.  Protect superstructure and substructure from stress transfer.

ACM-27 ACM-28

16- Discuss in detail the role of moisture barriers in buildings and their 2. Types:
materials. 1. Polymer Concrete (PC): Binder is entirely polymer.
Ans: Function of Moisture Barriers: 2. Polymer Modified Concrete (PMC): Cement + polymer admixtures.
 Prevent water ingress into walls, floors, and roofs. 3. Polymer Impregnated Concrete (PIC): Hardened concrete
 Protect building components from dampness, mould, and decay. impregnated with monomer and polymerized.
 Improve energy efficiency and indoor air quality. 3. Applications:
🔸 Types of Moisture Barriers:  Repair works, precast elements, drain covers, industrial floors.
1. Vapour Barriers: Control moisture from internal spaces.  Marine structures, chemical-resistant pipes, and tanks.
2. Waterproof Membranes: Prevent liquid water from entering. Advantages:
3. Breathable Membranes: Allow vapour out but stop water in.  High chemical resistance, fast setting, low permeability.
🔸 Materials Used: 19- Discuss the sustainability benefits of using industrial waste in
 Bituminous sheets, polyethylene films, EPDM, PVC membranes. concrete.
 Liquid-applied membranes (polyurethane, acrylic-based). Ans: Common Industrial Wastes Used:
🔸 Applications:  Fly Ash, Ground Granulated Blast Furnace Slag (GGBS), Silica

 Under concrete slabs, behind cladding, roofing systems, Fume, Rice Husk Ash, Waste Glass, Red Mud.
basements, and wet areas. 🔸 Sustainability Benefits:
17- Explain the various types of polymer foams used in construction.  Reduces cement usage, lowering CO₂ emissions.
Ans:  Converts waste into useful material (waste management).
1. Expanded Polystyrene (EPS):  Improves durability, resistance to sulphates, and reduced
 Lightweight, rigid foam. permeability.
 Used in insulation panels, flooring, and packaging.  Enhances workability and long-term strength.
2. Extruded Polystyrene (XPS):  Promotes circular economy in construction.
 Dense, moisture-resistant. 20- Explain the time-dependent changes in concrete including creep,
 Used for foundation and wall insulation. shrinkage, and corrosion.
3. Polyurethane Foam: Ans:
 Excellent thermal insulation. 1. Shrinkage:
 Spray-applied on roofs, walls, and pipes.  Volume reduction in concrete due to moisture loss.
4. Phenolic Foam:  Types: Plastic, Drying, Autogenous.
 Fire-resistant and good thermal insulation.  May lead to cracks, affecting durability.
 Used in ducts and industrial insulation. 2. Creep:
5. Polyethylene Foam:  Time-dependent deformation under sustained load.
 Flexible, shock-absorbing.  Causes long-term deflection in beams and slabs.
 Used in acoustic insulation and protective padding.  Influenced by load level, temperature, humidity.
Key Benefits: 3. Corrosion:
 Lightweight, thermal insulation, moisture resistance, and easy to  Steel in concrete corrodes due to chloride attack or carbonation.
install.  Results in cracking, spalling, and loss of strength.
Control Measures:
18- Describe in detail the composition, types and applications of  Use low W/C ratio, admixtures, proper curing, and protective
polymer concrete composites. coatings.
Ans:
1. Composition:
 Binder: Polymer resins (e.g., epoxy, polyester, vinyl ester).
 Aggregates: Sand, gravel, crushed stone.
 Additives: Fillers, fibres for enhanced properties.
 ACM-29 ACM-30

10 MARKS 3- Analyze the role of various industrial wastes in enhancing the

properties of concrete.
1- Elaborate on the mechanical and rheological behavior of fresh and Common Industrial Wastes Used:
hardened concrete.  Fly Ash: Pozzolanic, improves long-term strength, reduces heat of
hydration.
Ans: Fresh Concrete (Rheological Behavior):  GGBS (Ground Granulated Blast Furnace Slag): Improves durability
 Treated as a Bingham fluid: exhibits yield stress and plastic &sulfate resistance.
viscosity.  Silica Fume: Fills voids, improves strength & impermeability.
 Key properties:  Rice Husk Ash: Pozzolanic, enhances resistance to chemical attack.
o Workability (ease of mixing, placing)  Red Mud / Marble Dust / Copper Slag: Partial replacement for
o Cohesiveness cement/fine aggregate.
o Segregation and bleeding resistance Benefits:
 Influenced by:  Improves durability, workability, and strength
o Water–cement ratio  Reduces environmental footprint (waste recycling)
o Type and grading of aggregate  Reduces cement demand and CO₂ emissions
o Use of admixtures or fibres  Enhances resistance to alkali-silica reaction and sulfate attack
🔹Hardened Concrete (Mechanical Behavior): 4- Describe the mechanism, effects, and control measures of corrosion
 Compressive Strength: Main design parameter (e.g., 20–60 MPa+). of steel in concrete.
 Tensile Strength: ~10% of compressive strength. Mechanism:
 Modulus of Elasticity: Affects stiffness and deformation.  Carbonation: CO₂ reacts with Ca(OH)₂ → reduces pH → passive
 Creep: Time-dependent deformation under sustained load. layer on steel breaks → corrosion starts.
 Shrinkage: Volume reduction due to moisture loss.  Chloride Attack: Cl⁻ ions penetrate concrete → attack steel → rust
 Durability & Toughness: Resistance to weathering, loading, and formation → expansion and cracking.
fatigue. 🔹 Effects:
2- Discuss the detailed mix design of high strength concrete along with  Cracking and spalling of concrete
selection of materials.  Loss of bond between steel and concrete
High Strength Concrete (HSC) is defined as concrete with compressive  Structural failure risk
strength >60 MPa. It requires careful material selection and 🔹 Control Measures:
proportioning.  Use low-permeability concrete
Selection of Materials:  Use coated / stainless steel / FRP bars
 Cement: OPC 53 grade or blended cement (high early strength)  Provide adequate cover
 Fine Aggregate: Clean, zone II sand  Add corrosion inhibitors
 Coarse Aggregate: Crushed angular aggregates (10–20 mm)  Apply surface sealers and membranes.
 Mineral Admixtures: Silica fume, fly ash, GGBS (improve strength & 5- Compare high strength concrete, high density concrete, and
durability) lightweight concrete in terms of applications and properties.
 Chemical Admixtures: Superplasticizers (reduce water, improve
Property HSC HDC LWC
workability)
Strength (MPa) >60 25–40 15–40
 Water: Potable water, W/C ratio: 0.25–0.35
Mix Design Steps (Based on IS 10262 or ACI Method): Density (kg/m³) 2400–2600 >3200 <1900
1. Target strength: fck+1.65×Sf_{ck} + 1.65 \times Sfck+1.65×S Pumice, EPS, foamed
Aggregates Crushed granite, etc. Barite, magnetite
2. Choose W/C ratio slag
3. Estimate water and cementitious content Workability Requires admixtures Moderate Often lower
4. Calculate aggregate proportions Durability Excellent Good Moderate
5. Add admixtures (e.g., 1–2% superplasticizer)
Applications High-rise, bridges Radiation shielding Partition walls, slabs.
6. Trial mixes and testing

ACM-31 ACM-32

6- Discuss in detail the development, properties, and applications of 8- Analyze the constructional and architectural advantages of using
fibre reinforced concrete with case studies. sandwich panels and composites.
Development: Ans: Constructional Advantages:
 FRC is made by adding short discrete fibres (steel, glass,  Lightweight: Reduces dead load
synthetic, or natural) to concrete.  High thermal and acoustic insulation
🔹 Properties:  Fast installation, prefabrication friendly
 Increased tensile strength, toughness, ductility  Less foundation cost
 Better crack control 🔹 Architectural Advantages:
 Improved impact and fatigue resistance  Design flexibility
🔹 Types of Fibres:  Available in various finishes and colors
 Steel fibres: Structural uses  Suitable for curved and modern facades
 Polypropylene fibres: Shrinkage crack control 🔹 Typical Use:
 Glass fibres: Aesthetic panels  Prefab housing
 Natural fibres: Eco-friendly, low strength  Cold storage and clean rooms
🔹 Applications:  Roof panels and wall cladding
 Industrial floors, pavements 9- Describe the various types of elastomeric bearings and polymer
 Tunnel linings composites used in structures with examples.
 Precast panels Ans: Elastomeric Bearings:
 Shotcrete for slope stabilization  Plain Elastomeric Bearings: Absorb small movements
🔹 Case Studies:  Laminated Bearings: Steel plates + rubber → greater load transfer
 Delhi Metro tunnels: Steel fibre shotcrete  Pot Bearings: Large deformations, used in bridges
 Bridge decks in USA: Glass FRC overlays
 Sliding Bearings: Allow large translations
7- Explain polymer-based construction materials, their properties,
🔹 Polymer Composites:
types, and field applications.
Ans:Types:  FRP Sheets: Strengthening columns/beams
1. Polymer Concrete (PC)  GFRP rebars: Corrosion-resistant alternative to steel
2. Polymer Modified Concrete (PMC)  Carbon composites: High-strength retrofit materials
3. Fibre Reinforced Plastics (FRP) 🔹 Applications:
🔹 Properties:
 Bridge bearings, seismic isolation
 Lightweight, high tensile strength
 Retrofitting, corrosion protection
 Chemical and corrosion resistance
10- Write a comprehensive note on polymer concrete composites
 Durable and non-corrosive
including constituents, properties, design considerations, and
🔹 Applications:
applications.
 Structural retrofitting (FRP wraps)
Ans: Types:
 Waterproof coatings
1. Polymer Concrete (PC): Binder is a polymer resin (no cement)
 Expansion joints
2. Polymer Modified Concrete (PMC): Cement + polymer
 Non-metallic reinforcements
3. Polymer Impregnated Concrete (PIC): Hardened concrete
🔹 Common Polymers:
impregnated with polymer
 Epoxy, Polyester, Polyurethane, Acrylic
🔹 Constituents:
 Aggregates (normal/modified)
 Polymer resins (epoxy, polyester)
 Fillers (silica, fly ash)
🔹 Properties:
 ACM-33

High compressive & tensile strength

Excellent bonding and waterproofing
Fast curing
🔹 Design Considerations:
 Resin content (10–15%)
 Proper mixing & curing methods
 Chemical compatibility
🔹 Applications:
 Repair mortars
 Drainage channels
 Acid tanks, industrial floors
 Precast polymer manholes