THE EFFECTS OF GRAIN SIZE ON THE STRENGTH PROPERTIES OF COMPRESSED EARTH BRICKS: A RESEARCH PROPOSAL
Introduction
The strength of compressed bricks is a necessary quality outcome of bricking because it also reflects the desired engineering qualities that of density, durability and corrosion property. The concern of the strength of compressed bricks is also of utmost importance because it serves the very foundation of a building. A weak, less dense and less durable brick define a weak building.
Compressed bricks are made from locally available materials from the earth, either lime, sand, cement, clay and soil depending on what type of brick is built. The mixture is compressed using a pressure of 10 tons and for some 100 tons or more. Some grass, hemp or straw are used as binders especially for sun-dried compressed bricks. Kiln dried compressed bricks do not use the abovementioned materials as they burn in the fire. (Rebano-Edwards, 2010)
Compressed earth bricks are ideal for low-cost housing because it utilizes indigenous materials that cost very less. It is also energy efficient because it regulates the temperature by absorbing the heat on warm temperatures and releasing the heat on cooler temperatures. It is also environmentally friendly because it only utilizes energy efficient methods such as the sun and kiln plus the materials used are available in the environment. Finally compressed earth bricks are economically sound, because it provides employment opportunities to communities and also provide them with low-cost housing. (Rebano-Edwards, 2010)
Review of Related Studies and Literature
The concern among civil engineers and builders of compressed bricks is to enhance quality of compressive bricks by increasing its strength by reducing grain size. Grain size determines the compactibility, cohesion and plasticity of the soil. These in turn determine its fundamental qualities such as density, durability and compressed strength, water penetrability or absorption and abrasion. (Kamang and Osabo, 2001)
Kamang and Osaboa (2000) conducted a study on the effect of grain size on compressive strength, durability and density of earth bricks, using a 28-day curing period. They found out that the lower the grain size, the higher the compressive strength of the earth brick. A similar inversely proportional relationship is observed with grain size and density, that is, the higher the cement content, the lower grain size and the higher the density of earth bricks. These highly durable bricks were tested on abrasion test and moisture absorption. Density and compressive strength increased as cement stabilization increased to 6% to 10%. (Kamang and Osabo, 2000 and 2001)
Statement of the Problem
This study will find out whether grain size affects the strength properties of compressed earth bricks. Grain size is defined as the average size of a mineral particle (Answers.Com, n.d) which is also categorized into either coarse or fine (About.Com, n.d.).
Hypotheses
Strength properties refer to the density, durability, absorption and penetrability and compressive strength. This study hypothesizes that grain size is inversely proportional to density, durability and compressed strength.
Methodology
A preliminary test is necessary to determine the properties of the materials. The materials then follow the procedure of earth brick making. As soon as the materials are mixed they are compressed using a standard amount of pressure and moulded at a certain size and at certain stabilization levels for (for example 6 to 10), and dried and are tested for compressive strength, density, durability, absorption and penetrability, after 14 or 28 days.
Data Analysis
The values gathered from the different tests to measure grain size, density, durability, abrasion, absorption and compressed strength will be presented using a table and analyzed using a statistical program to measure possible relationship using coefficient of correlation and other statistical test.
REFERENCES
About .com, n.d., Grain Size Measurement. [online] Available at:< http://metals.about.com/library/bldef-Grain-Size-Measurement.htm> [Accessed 17 May 2011].
Answers.com, n.d., Grain Size. [online] Available at:< http://www.answers.com/topic/grain-size> [Accessed 17 May 2011].
Kamang, EEJ., Osabo, A., 2000. Grain Size Effects on the Durability and Strength of Stabilized Earth Bricks (CEB). Abstract only. Also published in Unijos, Journal of Environmental Studies, Volume 4;Number 1. [online] Available at: <http://dspace.unijos.edu.ng/handle/10485/508> [Accessed 17 May 2011].
Kamang, EEJ., Osabo, A., 2001. Grain Size Effects on the Durability and Strength of Stabilized Earth Bricks (CEB). Pdf. Also published in Unijos, Journal of Environmental Studies, Volume 4;Number 1. [online] Available at:< http://dspace.unijos.edu.ng/bitstream/10485/508/1/grain%20size%20effects%20on%20the%20durability%20and%20strenght%20of%20s0001.pdf> [Accessed 17 May 2011].
Rebano-Edwards, S., 2010. Building with Compressed Earth Bricks: Earth Construction for Low-Cost Housing. [online] Available at:< http://www.suite101.com/content/building-with-compressed-earth-bricks-a186724> [Accessed 17 May 2011].
Credit:ivythesis.typepad.com
Grain Size Analysis techniques are adopted by a lot of scientists because they are easy to use and some of the advanced software is also available which makes the work a lot easier for scientists all around the world.
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