JOMO-KENYATTA UNIVERSITY OF AGRICULTURE AND

TECHNOLOGY

COURSE: M.sc CONSTRUCTION ENGINEERING &

MANAGEMENT

COURSE UNIT: SUSTAINABLE CONSTRUCTION

COURSE CODE: ECE 3182.

LABORATORY REPORT-COMPARISON OF RAMMED EARTH,

STABILIZED SOIL BLOCKS AND QUARRY STONE WALLS.

PRESENTED BY:ETALE TUNYA

REG. NO: 0969/2009.

PRESENTED TO:PROF: OYAWA.

SEPTEMBER-DECEMBER 2009.

1.0 OBJECTIVES OF THE EXPERIMENT

The objective of the experiments is to compare the compressive strengths of:-

Stabilized earth wall. Rammed earth wall. Mansory wall - Ndarugu blocks

2.0 COMPRESSED STABILISED EARTH BLOCKS

The first attempts for compressed earth blocks were tried in the early days of the 19th century in Europe. The architect François Cointeraux precast small blocks of rammed earth and he used hand rammers to compress the humid soil into a small wooden mould held with the feet.

The Stabilized Compressed Earth Block (SCEB) Technology offers a cost effective, environmentally sound masonry system. The product, a stabilized Compressed Earth Block has a wide application in construction for walling, roofing, arched openings, corbels etc. Stabilized Earth Blocks are manufactured by compacting raw material earth mixed with a stabilizer such as cement or lime under a pressure of 20 - 40 kg/cm2 using manual soil press such as Balram, Makiga made soil press etc.

A number of manual and hydraulic machines are available in India. The basic principal of all the machines is the compaction of raw earth to attain dense, even sized masonry. Some of the hydraulic machines can even manufacture interlocking blocks. These interlocking blocks are highly suitable for speedy and mortar less construction. Stabilized Compressed Earth Block (SCEB) Technology helps in offsetting the use of fuel wood that is getting expensive every day. On the other hand, compressed earth blocks are sun dried and use cement as stabilization for gaining the required strength.

The soil, raw or stabilized, for a compressed earth block is slightly moistened, poured into a steel press (with or without stabilizer) and then compressed either with a manual or motorized press. But most of the times, they are stabilized with cement or lime. Therefore, we prefer today to call them Compressed Stabilized Earth Blocks (CSEB).

The input of soil stabilization allowed people to build higher with thinner walls, which have a much better compressive strength and water resistance. With cement stabilization, the blocks must be cured for four weeks after manufacturing. After this, they can dry freely and be used like common bricks with a soil cement stabilized mortar.

2.1 Materials, tools and procedure.

2.1.1 MaterialsThe material used in the in laboratory test are as follows 8 parts of soil (gravel). 7 parts of Nairobi quarry dust 4 parts of Ndarugu quarry dust 1 part of cement Water.

2.1.2 Tools and equipments. 2 trowels. 2 spades. 6mm sieve mesh. 1 wheelbarrow. 1 watering can. 1 factory broom. 2 buckets. 3mm brush. Lubricant. Manual block press.

2.1.3 Procedure. Sieve the soil using the 6mm sieve. Batch the soil and cement. Mix until cement and soil are mixed thoroughly. Sprinkle water on to the mix slowly while mixing. The moisture content should be about 10%. Scoop the mixture on to the block press and press. Eject the block gently from the machine and place in a

secure area. The process is repeated until the required number of blocks

are produced.

Cover the blocks, only uncovering once in the morning and evening during watering.

The blocks are cured for 7-14 days.

MANUAL BLOCK PRESS IN USE.

2.1.4 Test

Due to failure of the testing machine, the compressive strength test could not be carried out.

3.0 RAMMED EARTH

Rammed earth is a technique used in the building of walls using the raw materials of mud, chalk, lime and gravel. It is an ancient building method that has seen a revival in recent years as people seek more sustainable building materials and natural building methods. Because of the nature of the materials used it is incombustible, thermally insulating and very strong and hardwearing. It also has the added advantage of being a simple way to construct walls. Traditionally, rammed earth buildings are common in arid regions where wood is in scarce supply.

Using it involves a process of compressing a damp mixture of earth that has suitable proportions of sand, gravel and clay (sometimes with an added stabilizer) into an externally supported frame that moulds the shape of a wall section creating a solid wall of earth. Traditional stabilizers such as lime or animal blood were used to stabilize the material, but cement has been the stabilizer of choice for modern times. However the use of cement is contentious as its manufacture creates 10% of manmade carbon emissions.

After compressing the earth the wall frames can be immediately removed and require an extent of warm dry days after construction to dry and harden. The structure can take up to two years to completely cure, and the more it cures the stronger the structure becomes. When the process is complete it is much like constructing a handmade wall of solid rock.

Formwork is set up creating the desired shape of the section of wall; damp material is poured in to a depth of between 100 to 250 mm. A pneumatically powered backfill tamper — something like a hand-held pogo stick with a flat plate on the bottom or even a manual tamper — is then used to compact the material to around 50% of its original height. Further layers of material are added and the process is repeated until the wall has reached the desired height. The wall is so solid that, if desired, the forms can be removed immediately. This is necessary if wire brushing to add texture is desired; otherwise walls become too hard to brush after around 60 minutes. Walls take some time to dry out completely, but this does not prevent further work on the

project. Any exposed walls may be sealed to prevent water damage — there are several proprietary products specifically designed to seal earth walls.

3.1 Materials, tools and procedure. 3.1.1 MaterialsThe material used in the in laboratory test are as follows

8 parts of soil (gravel) 7 parts of Nairobi quarry dust 4 parts of Ndarugu quarry dust 1 part of cement Water.

3.1.2 Tools 2 trowels. 2 spades. 6mm sieve mesh. 1 wheelbarrow. 1 watering can. 1 factory broom. 2 buckets. Formwork (steel plates). Iron tamper.

3.1.3 Procedure.

Sieve the soil using the 6mm sieve. Batch the soil and cement. Mix until cement and soil are mixed thoroughly. Sprinkle water on to the mix slowly while mixing. The moisture content should be about 10%. Scoop the mixture into the already assembled formwork. Tamp manually till it is firm. The process is repeated in layers of about 100mm till the

desired height is achieved. The formwork is removed.

3.1.4 Test

Due to failure of the testing machine, the compressive strength test could not be carried out.

4.0 MASONRY WALL.

A masonry wall is a wall made from materials which have traditionally been cemented together with the use of mortar. Masonry walls can be used as structural walls in buildings, and they can also be utilized to create barriers between property lines or different areas on a property. People have been working with masonry in construction for thousands of years, as ample examples of surviving masonry walls from all over the world illustrate. Properly maintained, masonry can also last a very long time; masonry walls from the medieval era, for example, are still in use in parts of Europe, and the Great Wall of China is a particularly notable example of a masonry wall.

Stone blocks used in masonry can be dressed or rough. Stone masonry utilizing dressed stones is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Both rubble and ashlar masonry can be laid in courses (rows of even height) through the careful selection and cutting of stones, but a great deal of stone masonry is uncoursed.

Manufactured-stone, or cultured stone, veneers are popular alternatives to natural stones. Attractive natural stone has become more expensive in many areas and in some areas is practically unavailable. Manufactured-stone veneers are typically made from concrete. Natural stones from quarries around the world are sampled and recreated using molds, aggregate, and colorfast pigments. To the casual observer there may be no visual difference between veneers of natural and manufactured stone.

4.1 Materials, tools and procedure.

Since materials (quarry stones) could not be availed on time, the experiment was not carried out.

5.0 REFERENCES:

Allen, Miles, Out of the Ground – Earthbuilding in New Zealand, Dunmore press, Palmerston North, 1997, ISBN 0 86469 290 9.

Hodder, Gary, Earth Building Non Specific Design Guidelines, Published by Gary Hodder Consulting Registered Engineer, Nelson, 1991.

Howard, Ted, MUD AND MAN A History of Earth Buildings in Australasia, Earthbuild Publications 1992, ISBN 0-646-06962-4.

Hydroform machine, training and building manual (2004).

Kennedy, Joseph F. "Building With Earthbags." Natural Building Colloquium. NetWorks Productions. 14 Feb. 2007.

Khalili, Nader. "Nader Khalili." Cal-Earth. 19 Jan. 2007

Middleton, G.F., revised Schneider, L.M.,Bulletin 5 Earth-Wall Construction, 4th Edition, National Building Technology Centre, 1987, ISBN 0-642-12289-X.

The Green Building Program. "Earth Construction." Sustainable Building Sourcebook. 2006. 14 Feb. 2007

http://en.wikipedia.org/wiki/Rammed_earth

www.wisegeek.com/what-is-a-masonry-wall.htm.