A Review on Bricks and Stabilized Compressed Earth Blocks

Scientific Research and Essays Vol. 6(3), pp. 499-506, 4 February, 2011 Available online at http://www.academicjournals.org/SRE DOI: 10.5897/SRE09.356 ISSN 1992-2248 ©2011 Academic Journals Review A review on bricks and stabilized compressed earth blocks Sadek Deboucha* and Roslan Hashim Department of Civil Engineering, Faculty of Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia. Accepted 18 March, 2010 This paper is a review of the state of uses of clay bricks and stabilized compressed earth blocks. We offer an overview of the world general building using clay bricks or stabilized compressed earth blocks compiled from various research organizations, modern projects which have been carried out and reports from existing manufacturing of clay bricks or stabilized compressed earth blocks. Although, stabilized compressed earth blocks as construction materials are highly unknown to most people, its advantages are seen in terms of rescuing the heritage and also as rediscovered environmentally- friendly building materials. Key words: Clay bricks, stabilized compressed earth blocks. INTRODUCTION The history of civilization is synonymous to the history of water and allow mosquitoes to breed. Extensive sand masonry. Man’s first civilization, which started about 6000 mining can lower the river- beds and allow salt-water years ago, was evident from the remains of the intrusion inland. Therefore, the development of many Mesopotamians masonry heritage. During those days, alternative walling materials as possible will be of masonry buildings were constructed from any available immense benefit to minimize the impact on the environ- material at hand. The Mesopotamians used bricks, made ment. Earth can be used for construction of walls in many from alluvial deposits of the nearby River Euphrates and ways. However, there are few undesirable properties Tigris to build their cities beside two rivers. Where such as loss of strength when saturated with water, civilization existed in the vicinity of mountains or rocky erosion due to wind or driving rain and poor dimensional outcrops, stone was used. The Egyptian pyramids that stability. These draw backs can be eliminated signify- existed along the rocky borders of the Nile valley were cantly by stabilizing the soil with a chemical agent such examples of such stone masonry. In the Eastern as cement. Cement stabilized soil is generally used as civilization, remains of historical masonry are the reputed individual blocks compacted either with manual Great Wall of China, which is considered as one of the hydraulically operated machines. Significant research seven construction wonders in the world. data are available for these applications either as block The prevision of good quality housing is recognized as strength or wall strength (Perera and Jayasingh, 2003; an important responsibility for welfare of people in any Reddy and Jagadish, 1989). country. For this, building materials based on natural The early forms of masonry application in Malaysia resources are often used. Some examples are the use of dated back about 350 years ago with the construction of clay for making bricks, and river sand for making cement the Stadthuys in Malacca, built by the Dutch in 1650. The sand blocks. The commercial exploitation of these British colonized the Malaysia Peninsula initiated a more resources often leads to various environmental problems. modern form of masonry construction. Brickwork If clay mines are not properly filled up, they can collect buildings were at that time built specially for government offices, quarters and residential homes. The administra- tive block, Sultan Abdul Samad building built in 1894 and given a face-lift during the Fourth Malaysia Plan (1981- *Corresponding author. E-mail: [email protected]. Tel: 1985) is an example of a masonry heritage, which stands 6016 981 8692. Fax: 603 7967 5318. as a remarkable landmark of Kuala Lumpur. During the 500 Sci. Res. Essays standardization of physical properties of the final product at all. Among the problems faced by the industry, the first and probably the most important is the supply of reasonably priced fuel in the form of fuel wood as walls as coal. A second major problem is that the industry is not walls organized and technically ill prepared with very little know-how about it and few engineers and scientists having taken interest in this industry (Egbert, 1993). The history of brick industry is very old and can be traced back to about 5000 years old. Understanding of the brick, microstructure as influenced by the range of temperature during firing cycle has been enhanced by the experimental work in this area. For example, Convile et al. (2005) investigated the micro-structural evolution of various clays using XRD and TEM. They observed that, the pseudo-hexagonal morphology of the kaolinite changed to pseudo-hexagonal meta-kaolin at around Figure 1 . Sultan Abdul Samad building 1894 Kuala Lumpur. 550°C with meta-kaolin broken down at temperatures > 900°C to γ-alumina-type spinal and a silica-rich phase. The spinal type phase started to transform into mullite at last few years, there has been a growing interest in the > 1000°C. At 1300°C, mullite increased in size to ~1 µm use of earth as a modern construction material and also and in some regions, cristobalite formed from the silica considered as a sustainable material. Some of the rich matrix (Convile et al., 2005; Lee et al., 1999). XRD, reasons for this are the energy saving in manufacturing TGA/DTA and EF-TEM studies of clay have revealed that compared to clay bricks, the cement used was compared meta-kaolin partially transforms to γ-alumina at 920°C to concrete blocks, the transport savings, if soil comes (Peters and Iberg, 1978) Figure 1. On further increase in from the construction site or vicinity and the natural the firing temperature to > 940°C, the crystallization of appearance and colours that help buildings integrate into Al2O3-rich mullite began and excess amorphous silica the landscape (Carmen and Ignacio, 2005). In Malaysia, was discarded into the matrix (Peters and Iberg, 1978). there is more research needed in the area of stabilized Mullite begins to crystallise at 1050°C and its crystal size earth for constructing materials and the problems faced in increases with increase in firing temperature (Convile et using it today. al., 2005). A number of phases are usually present in fired bricks. Quartz is observed in all samples, usually less abundant in the brick than in the raw material. Production of earth materials Hematite is also present in all samples, which impart the red colour to bricks. Even in yellow bricks, the presence Clay bricks of Hematite is observed though in smaller amounts (Amjad, 2000). Brick is a ceramic material mainly used in construction industry. Its production process involves forming of clay into rectangular blocks of standard size, followed by firing Clay brick strength to temperature ranging from 900 - 1200°C1. It is made of clay or shale and when given desired shape is dried and Compressive strength of brick is important as an indicator fired into a durable ceramic product. Brick is one of the of masonry strength and as a result brick strength has most important building materials. Energy consumption become an important requirement in brickwork design. A and pollution are the two important environmental and considerable amount of past research and studies on cost concerns related to the brick industry. A report, in masonry indicated that stronger bricks contribute to 1993, indicated that more than 3000 brick kilns in greater brickwork strength (Hendry, 1990; Lenczer, 1972; operation in the country with an annual growth of 3% Sahlin, 1971). (Egbert, 1993). Old rubber, low quality coal, wood and In Singapore, Standard SS 103 (1974), compressive used-oil were reported as fuel in most brick kilns. strengths are classified as First, Second and Third Grade Consumption of these fuels, combined with inefficient with minimum compressive strength of 35, 20 and 5.2 2 combustion process produces large quantity of N/mm , respectively. Figure 2 shows the relationship hazardous gases that threaten the environment as walls between strength of brick and strength of wall. The British as those working in brick kilns. Since long, in fact, the standard (BS, 3921, 1985) categorized compressive brick-industry in the country has remained mostly strength into classes of engineering A and B presented in traditional with no importance to enhancement or Table 1. These classifications of bricks commonly used Deboucha and Hashim 501 Figure 2 . Mean compressive strength of walls against strength for 102 mm thick brickwork in various mortars Hendry, (1990). Table 1 . Classification of bricks by compressive strength and water absorption (BS 3921:( 1985) Class Average compressive Water absorption (5 h Boiling) % by Strength ( ) weight Engineering A ≥70 ≤4.5 Engineering B ≥50 ≤7.0 Damp-proof course 1 ≥5 ≤4.5 Damp-proof course 2 ≥5 ≤7.0 All others ≥5 No limits for construction with aesthetics and strength require- boiling test gives fully saturated condition where all pores ments. All other brick and damp proof- course bricks are filled up with water. The saturation coefficient ranges should have strengths not less than 5 N/mm 2. However, from about 0.4 - 0.95; the lower value of around 0.4 the damp-proof course is divided into two in accordance indicates high durability and higher values of around to water absorption. 0.95, low durability (Khalaf and Venny, 2002). Other In the American Standard (ASTM), compressive durability indices have also been developed based on strengths are classified in accordance to the different relationship of porosity and water absorption. Table 4 grades of weathering and exposure condition as shows the durability indices developed by Surej et al. indicated in Table 2.

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