THE ROLE OF SOIL CEMENT BLOCKS IN HOUSING

INDEX

INTRODUCTION NEED FOR ALTERNATIVE BUILDING MATERIALS MANUFACTURING PROCESS RESULTS, COST ANALYSIS ADVANTAGE’S & DESADVANTAGE’S WORKS DONE CONCLUSION SCOPE FOR FURTHER STUDY

INTRODUCTION

Soil Cement Blocks or Compressed Stabilized Earth Blocks (CSEB) are dense solid blocks compacted using a machine with a mixture of soil, sand, stabilizer (cement/lime) and water.

Standard sizes are (305x143x100mm) and (230x190x100mm).

AT 7% of cement the wet compressive strength of 3-4Mpa. can be obtained.

INTRODUCTION (cont.)

CSEB can be used for wall construction without any new technological problems.

The Soil cement blocks can be constructed using cement mortar, lime mortar, lime pozzolana mortar or mud mortar.

Normal cement mortar of 1:6 proportion has been used in the construction of soil-cement block walls of several buildings. To improve the bonding frogs have been

introduced on both faces.

INTRODUCTION (cont.)

NEED FOR ALTERNATIVE BUILDING MATERIALS

Demand for new buildings as well as the cost of building construction is growing at a steady pace.

Bricks, cement, steel, timber, plastics, glass, are some of the commonly used conventional materials .

Manufacturing processes are detrimental to the environment.

Use of conventional materials alone to satisfy the demand for new buildings, can drain the available energy resources and cause environment degradation.

Center for ASTRA (Application of Science and Technology to Rural Areas) formed in the Indian Institute of Science, Bangalore, has developed alternative building technologies looking at utilization of local materials and reducing energy consumption to achieve cost reduction.

MANUFACTURING PROCESS

Soil Suitability and Stabilization for CSEB Not every soil is suitable for CSEB in particular. Top soil

and organic soils must not be used. A good soil for CSEB is more sandy than clayey.

Soil Identification: Grain size distribution, to know quantity of each grain size. Plasticity Characteristics, to know the quality and

properties of the binders(clay and silts) Compressibility, to know the optimum moisture content,

which will require minimum of compaction energy for the maximum density.

Cohesion, to know how the binders bind the inert grains. Humus content to know if there are organic materials

which might disturb the mix.

Stabilizer proportion:

Cement stabilization = 5% average

The minimum is 3% and the maximum is 8%

Lime stabilization = 6% average

The minimum is 2% and the maximum is 10%

Curing The mud blocks stabilized with cement or lime must be

cured for 21 days by a gentle sprinkling of water. The top of the stack of blocks must be covered by straw

or gunny cloth to prevent evaporation of water. After 28 days curing, the stabilized mud blocks (SMB)

are used for wall construction.

TEST RESULTS, COST ANALYSIS

TABLE-1

Change in compressive strength with extra pressure and extra cement

Figure-1

Cost effectiveness

A finished m3 of CSEB wall is generally:

48.4 % cheaper than wire cut bricks.

23.6 % cheaper than country fired bricks. Energy consumption (Kg of CO2 /M2)

4.9 times less than wire cut bricks

15.1 times less than country fired bricks

ADVANTAGE’S

A local material. A bio-degradable material. Limiting deforestation. Energy efficiency and eco friendliness. Cost efficiency An adapted material A transferable technology A job creation opportunity Flexible production scale

DISADVANTAGES

Ignorance of the basics for production & use Wide spans, high & long building are difficult to do Low technical performances compared to concrete Untrained teams producing bad quality products Over-stabilization through fear or ignorance Under-stabilization resulting in low quality products Low social acceptance due to counter examples

WORKS DONE

BUILDING WITH EARTH IN AUROVILLE

Building with arches, vaults and domesTraining Centre of AV-BC Mirramukhi School

With stabilized earth 10.35 m span

waterproofing Built in 3 weeks

CONCLUSION

Building with earth is cost and energy effective technology.

It requires less energy than all of the available competitors and slightly less cement than most of them.

To utilize local materials and be manufactured either on-site or locally makes the material more suitable to cottage industries and self-build schemes.

SCOPE FOR FURTHER STUDY

The high-density compressed and stabilized soil block seems to be a reasonable Contender in low-cost building materials.

The ability for the CSEB to utilize local materials and be manufactured either on-site or very locally makes the material more suitable to cottage industries and self-build schemes.

Many different variants of the CSEB have already been successfully made.

Following that it would need to be tested to determine whether or not it exhibits the necessary level of durability for

use in the humid tropics.

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