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9.2ubble Work

Rubble foundations are suitable when soil is wet and are constructed using irregularly shaped crushed stone ranging from 9x6 to 9x4 inches. The rubble is laid without systematic bonding in random rubble masonry. Large rubble is placed on the bottom with flat surfaces vertical and voids filled with smaller rubble and mortar. Foundations for the site were constructed using random rubble masonry laid on a screeded concrete base with voids filled with mortar and stones meeting specifications for hardness, size, and defects.

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Malith De Silva
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68 views2 pages

9.2ubble Work

Rubble foundations are suitable when soil is wet and are constructed using irregularly shaped crushed stone ranging from 9x6 to 9x4 inches. The rubble is laid without systematic bonding in random rubble masonry. Large rubble is placed on the bottom with flat surfaces vertical and voids filled with smaller rubble and mortar. Foundations for the site were constructed using random rubble masonry laid on a screeded concrete base with voids filled with mortar and stones meeting specifications for hardness, size, and defects.

Uploaded by

Malith De Silva
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOC, PDF, TXT or read online on Scribd
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9.

2UBBLE WORK
If the soil is wet it is more suitable to erect foundations using Rubble than bricks. To erect
a Rubble foundation, it was used 9x 6 & 9x 4 Rubble. These are crushed from the query.
Therefore this Rubble hasnt a standard shape or size. Because of this it cannot be laid rubble
systematically in this type of bonds. Therefore these bonds are called random rubble masonry.
Although there isnt a systematical method to lay rubble in these bonds, following methods are
taken to erect the foundation with maximum strength.
1. First largest rubble was placed in the bond. The flat surface was placed vertically on the
bottom.
2. Care must be taken not to erect the bond with continuous vertical joints.
3. All the voids between large Rubble must be filed with small Rubble partials. The
remaining small voids were filled with 1:5 cement, sand, mortar mix.
In this site Rubble wall foundations were erected between columns at some places, according to
the given detail drawings
First the trenches were excavated and the base was concreted using mass concrete. 50mm
100mm thick screed concrete (1:3:6) was placed to get a hardened and leveled surface to erect
the rubble wall foundation. Rubblework is difficult than other bonds. This is because of rubble is
having various sizes. Approximately rubble is 6x 9 size. Quantity required for cube volume
depends on the size of the rubble. Normally rubble required for one cube in the bond is 1.3cubes
of Rubble. This is because when doing rubblework it should be arranged very closely with small
pieces. Mortar mix used for rubblework is 1:5 cement, sand mixture. When doing rubblework
mortar mixture must be pushed in to the holes between rubble well, using trowel. Using plum bob
it must be constructed vertically.
In our site, foundations were constructed with random rubble masonry.
Screed concrete of 50mm thickness was placed before rubble work start. Width & required length
was marked on it using Theodolite, plum bob, steel tape. The construction stones were cleaned
and free of dust and it was wetted before use.
The boulders should be hard, free from decay, weathering and defects like cavities,
cracks, flaws, sand holes, etc. And stones with rounded surfaces were not used. The length of the
stone should not exceed three times the height. The thickness if these stones in any direction were

not less than 100 mm. The use of chops was restricted to the filling of interstices between the
adjacent stones in hearting, and those were not exceeding 20 % of the quantity of stone masonry.

The all inter fillings was done using the 1:5 cement mortar and compacted
gently using the trowel. When the foundation is rising out from the ground level the
strings must be aligned

according to the drawings. The strings should be aligned

vertically at about 6 inches. The any voids on the sides of the foundation should be
covered using the

1:5 cement mortar. It is better if we can pour water on the

foundations that helps to gain the strength.

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