Mud Brick in Building Construction

Building Construction

The use of earth construction is well established in energy Building Construction efficient housing. Mud bricks consist of clay, water, and binding material such as rice husks or Building Construction straw. The advantages of mud brick include its low-cost and great thermal behavior. Although mud brick is considered one of the oldest construction materials, engineers and builders do not have enough information about its mechanical properties. Also there is no accurate design code to follow before construction. This study is devoted to enhance the low compressive strength of mud brick without sacrificing its low thermal conductivity properties. The experimental program in this research includes the use of different admixtures to increase the compressive strength of the basic mud mix. The experimental results show that the increase of cement ratio, as ingredient to a certain limits, can lead to an optimum compressive strength of the brick.

Earth as mud bricks, has been used in building construction for thousands of years and approximately 30% of the world’s present population still live in earthen shelters [1] . Mud brick is an inexpensive, environmentally- friendly and abundantly-available building material. It has been used extensively for building construction around the world, particularly in extreme hot, dry desert climates like that of most Arabian countries [2] . In these countries, mud bricks are made by blending mud and water together into a goopy mixture. Traditionally straw is added to improve tensile strength, and may prevent mud bricks from cracking. The mud brick is then shaped in a mold of almost any size or shape, or by hand. The brick mixtures are then laid to dry in the heat of the sun for about 25 days before use [3] – [6] . Figure 1 shows new unlaid mud bricks in the Jordan River, while Figure 2 shows buildings made from mud bricks in an old town in Niger.

Mud bricks have several advantages over other conventional building materials, e.g., concrete masonry. These advantages include: a very minimal manufacturing process; skilled labor is not necessary; mud is available from natural resources; inexpensive construction materials; and mud structures are able to perform satisfactorily under hot environmental conditions [7] . However, there are many disadvantages in using mud bricks as building materials. These include: mud brick may tend to erode under rain impact; absorption of water causes swelling of mud brick, while evaporation of water from the mud brick gives rise to shrinkage and cracking; and mud brick is a relatively fragile material, which cannot resist earthquake hazards.

It is known that mud brick technology has been widely used in desert countries due to the widespread existence of silt and clay deposits in these areas. The importance of using mud brick as a building material, however, has not been seriously investigated through scientific experimentation. Therefore, this study aims to investigate: improvements in mud brick consolidation by increasing its durability; and imparting water penetration to mud brick. In this research, the effect of different mud brick components on strength and thermal conductivity properties are investigated. The basic mixture consists of mud (clay and sand), straw and water. Many additives are provided to the basic mixture in order to improve brick properties.

The overall aim of this study is to determine, through extensive experimental investigation, the effect of different mud brick ingredients on strength and absorption, and utilize these results in a forthcoming study on thermal-conductivity properties. With this in mind, the specific objectives of the study are to improve mud brick consolidation by using materials such as soluble silicate, ethoyl silicate, silanes or siloxanes, isocyanates and various polymers agents to treat mud brick permeability. In addition, the effect of using metallic fibers to improve mud brick durability is investigated.