Improving the Properties of Clay Soil by Using Laterite Soil for Production of Bricks

Abstract Nowadays, the utilization of locally accessible materials is a crucial stage for sustainable, economical building material on the earth’s surface. Within them, brick is one of the commonly used construction materials around Jimma town due to the availability of clayed soil. Nevertheless, brick produced by small micros unskilled enterprises rather than by traditional methods, its quantity was small, and its quality was unsatisfactory because it can easily break, and it has high water-absorbing conduct. The purpose of the investigation was to improve the properties of clayed soil properties by using laterite soil for the manufacturing of bricks for masonry units. In order to achieve this, research used non-probability sampling techniques to collect samples in Jimma area. Then, the collected samples prepared for different laboratory tests and by partially replacing literate soil by 5 %, 10 %, 15 % and 20 % on a clayed soil in order to get optimum property by different mix ratio for different laboratory tests results indicated showed that the lightweight bricks could be made from the approach of this study without any deterioration in the quality of bricks. Additionally, the compressive strength of the blocks optimum at 15 % lateritic soil replaces in clayed soil contents. The optimum firing temperature furnace at a duration burning of brick was at 1000 °C for 5hrs. It has shown that bricks prepared of clay-laterite earth capable of high resisting capacity rather than for beauty.


Introduction
Ethiopia one of the fast economic growth in East-Africa [1]. Due to urbanization the number of populations living in town becoming increases day to day ; so that for sustainable living standard in a town constructing a house un-questionable for human being although the cost of a unit black of plain concrete highly increases [2].There was small number of micro enterprises production clay brick with traditional way without controlling the quality only by looking a brick face beauty but there was a large deposit of clay soil and literate soil in Jimma area.
Laterite earth material was considered to be one of the oldest and commonly used building materials. It was considered to be one of the most important construction material in the world wide [3]. Unfortunately, laterite earth construction in developed country is diminishing with the abrupt changes in construction materials and methods [4]. Good quality bricks can be manufactured using lateritic soil provided that accepted clay material will be added. The use of plastic clay alone in the production of brick may not be suitable due to shrinkage and warping effect during the drying process [5].
According to Yar'adua Muntari Mudi (2012), the application of lateritic brick added clay started around 8000BC in Mesopotamia the construction of houses, dams, and roads. Mostly of builders and construction peoples value most of the soil. Due to it durability and cost effectiveness. It can be considered also as an excellent sustainable material in construction and recycling process for it can minimized pollution and has low carbon emission during the application [6]. The application of laterite earth in building construction almost exist anywhere in the world especially in third world country.in country like Kano, Kaduna and other cities in Northern Nigeria, used of this material is very effective. But it can be noted that laterite earth is also applied in developing countries [7;5]. In many countries, in Asia and Africa , more than two billion peoples are using in building/house construction using lateritic earth and clay products. The application of these material has earned lot of advantages by determining it quality, identifying its characteristics and its application in construction.
Additionally, it improve the quality of lateritic earth, additives and remove of one of its contents is also an option [8]. The reduction of energy requirement in the production of brick using lateritic soil is an advantage. It will be produce using 5KWH/m 3 compared to fired brick and concrete block which consume 1000 kWh/m 3 and 450 kWh/m 3 respectively. Additionally, lateritic soil structure are easily recyclable without polluting the environment [9]. Due to it availability /existence ant where in the world, the application of its uses in environment building construction is very crucial. It available in many different composition which need further investigation when added to other material such as clay to produced sustainable structure [10-11;5]. Brick extensively adopted building material round Jimma town. unlike other than city outside of jimma used most implemented for villa houses, fences, existing old buildings and fences are intensively constructed using brick wall and columns.
Particularly ancient structures brick columns and walls are very exciting which occur today without major failure and attending still current time. But the research conducted shown by [12] shows that, the brick produced nearby jimma area where below standard specification.In addition, small micros are producing clay brick for low cost houses these days in small amount and with unsatisfactory quality, which can easily break and high water absorbing behavior. It is also known that many people are not using this day's for load bearing rather for beauty and fence purpose only. This study was improve the physical properties of the brick by mixing clay soil with literate soil. So based on this it encourage the use of locally available material for the production of brick for affordable and low cost construction of housing, this study was good opportunity for Job Creation for the society.

Materials required
Purposively; Lateritic soil and with High plastic clay soil collected at depth of 0.5m in order to protect other organic material.

Preparation of Brick
The clay soil were used in this study was selected with highly plastic contents. In order to improve the property of the clay soil by different percentage laterite soil were 5%, 10%, 15% and 20% (by weight) was used and finally uniform mixing was carried until the same colour was obtained. Atterberg limit tests were performed on different percentage of lateritic soil added on clay soil. Water was added in the mixes prepared until it give a consistency, workable and suitable for different percentage of brick preparation and proper mixing was done in the preparation of bricks.
The following procedure were used during production of clay-lateritic brick units o The collected sample lateritic and clay soil allowed to drying separately o By breaking the samples and grinding in small particles until the required sieve size pass.
o Preparing mix design (according to the percentage) required and separately by adding the necessary quantity of water for different mix until the favourable for workability ,finally mix stored in a cool room for at least for two days until uniform distribution of water attained in the mixture.
o Before molding start; mould was dipped in water in order to prevent sticking and poured the mix in the mould by thrown forcedly by hand until it a roughly shaped attain. The excess on the top of mould was removed by thin wire cable. Immediately; the moulded brick was demolded and dried in the sun for a week and finally the bricks were a furnace oven dried at 1000°c.

Identification of engineering properties of lateritic soils.
In order to control the quality of the materials, laboratory tests were carried out based on the specification. The tests involved to classify the properties of the lateritic soil such as its physical and mechanical properties.

Engineering properties of untreated Clay soil.
The tests involved to classify the properties of the clay Soil such as its physical and mechanical properties. The tests carried out on the unprocessed clay soil include sieve analysis, Atterberg limit test, compaction test, California bearing ratio and specific gravity.

Preparation of mixed clay-lateritic soil
As a control of test a clay brick alone was prepared accordingly and shaped based on size of box and allowed to burnet to a furnace oven. In addition to this different percentage of laterite soil was added 5, 10, 15 and 20%. The blends were set with the pre-determined optimum moisture content values.
The size of box of bricks to be casted dimension of 230 x110x70mm non-modular bricks. It's obvious as per IS 1077:1992. The arranged combination was forced into the mould and subsequently removing the mould retained it for sun drying. The prepared sample of bricks was allowed to dry until it reduces moisture content from it. Exposing to ventilation to sun drying period approximately a weeks and finally transferring the samples to the furnace oven, where it was burned at a temperature of 1000 o C.
Sample of bricks was taken out from the furnace oven after that allowed to cool then starting the laboratory testing started after 21 days of curing as per IS code.

Test Methods
The bricks were tested as per IS code for finding the physical properties. The burned bricks were cured for 21 days and only after that testing were started. Compressive strength, water absorption, efflorescence and thermal conductivity are the tests conducted on the bricks. These tests were conducted as per IS 3495 (PART I-III) and as per IS 3346:1980.

Discussion of Test Result
Clay bricks made with laterite soil were tested for analyzing the physical properties of bricks such as Atterberg limit test, compressive strength, water absorption, efflorescence and thermal conductivity.

Atterberg limit test and workable mixing water contents
The results of Atterberg limit tests and workable mixing water contents are shown in Table 3.3 and

Linear shrinkage and density
The summary of the results of linear shrinkage, and dry and firing densities are shown in Table 3.4 the shrinkage decrease with increases the laterite soil contents but decrease in dry density.  Mpa, which belong to class designation 100 as per Indian standard specification. All the modified bricks show higher strength than control bricks.

Water absorption
As the percentage of laterite soil increases water absorption decrease.  shows lesser water absorption rate compared to standard specification of the class.

Efflorescence
Efflorescence was determined for find the alkaline salt content in bricks. The test was conducted as per IS 3495 (part III) -1992. In this experimental work no perceptible deposit is observed on majority of samples but there is a very thin deposit of salts observed on some parts of samples

Conclusion
On the basis of test results, the following conclusions can be drawn: 1. The Laterite soils were classified based on ASSHTO classification system as A-2-7 category with poorly graded gravel and based on the USCS classification system as SC soil groups. The compaction test for the laterite soils yielded MDD and OMC which 1.329g/cc and 40.8% & The Clay soils were classified based on ASSHTO classification system as A-2-7 category with high plastic clay and based on the USCS classification system as CH soil groups. The compaction test for the Clay soils yielded MDD and OMC which 1.26g/cc and 35.8% respectively 2. The density of brick decreases with increase in laterite contents. Light weight bricks can thus be produced without any deterioration in the quality of the bricks.
3. Modified clay bricks show increase in compressive strength up to a particular percentage, beyond that point compressive strength decreases. This is due to the less bonding between clay-lateriate and lesser density of the modified bricks. Water absorption decreases with increase percentage addition lateriate soil. This is due to the courser soil particles in bricks; this results in less water absorption. all the bricks have slight efflorescence content. This shows the alkaline salt content in those bricks are less.