A review of the use of lateritic soils in the construction/development of sustainable housing in Africa: A geological perspective

Abstract

Highlights• Appraisal of the previous work in the use of tropical soils in low cost, energy efficient housing development.• It established CEBs as sustainable building materials for a sustainable environment.• Identification of lateritic soils as suitable material in the production of CEBs.• Established the importance of parent rock material (its type and mineralogy) in strength and durability of CEBs.• Discouraging the common practice of firing clay bricks for the sake of sustainable environment. AbstractLateritic soils have been described as highly weathered tropical or sub-tropical residual soils with varying proportions of particle sizes ranging from clay size to gravel, usually coated with sesquioxide rich concretions. It is sometimes referred to as brick earth based on its use. The use of laterite and lateritic soils have been found to promote the realization of decent housing and bridging the housing deficit, especially in Africa.The author has attempted to review available information on the recent trends in building bricks and housing development with the aim of identifying a suitable soil material that will meet the present challenge of sustaining the environment without costing too much and maintaining a high standard of strength, durability and aesthetics. A critical review of laterite and lateritic soils from a geological point of view indicated these soils to be one of the best natural materials used in the production of compressed earth bricks. Lateritic soils are mostly well graded, comprising both cohesive (silt and clay) and cohesionless (sands and gravels) soil fraction, it contains sesquioxides and clay minerals which are very useful in the natural binding process as well as in the presence of most chemical binders.Compressed earth bricks are mainly composed of raw earth materials (soil) with their cohesion due principally to the clay fraction present in both humid and dry states. CEB's promote building in a 'sustainable' way and offers a good prospect to using our resources in an efficient manner while creating dwellings that improve human health, well-being and preserving a better environment, with an affordable and natural alternative.

Geotechnical characterisation of lateritic soils from south-western Nigeria as materials for cost-effective and energy-efficient building bricks

“…A high clay content will not be acceptable due to high expected shrinkage in CEB"s produced from such soils. Although stabilisation with lime has been suggested for soils with more than 35% clay, it may not be economical (Houben and Guillaud 1994;Oyelami and Van Rooy 2016). The soil index properties were found to have a significant influence on brick strength at a 10% level of significance as estimated through the F-test while the plasticity index was found significant at 5% which reflects a strong influence on the strength of bricks ( Table 4).…”

“…The effect of grain size distribution is reflected on the brick strength (Table 6), It was found that lateritic soils derived from the schist belt region (OS) tend to give higher brick strengths due to the specific particle size distribution (higher amount of fines), amount of stabiliser added i.e. 5% and more importantly, the load at compression (compaction pressure) (Adam and Agib 2001;Oyelami and Van Rooy 2016). Based on the fact that a low pressure manual mould was used, the load at compression depended partly on the effort of the human operator.…”

“…Governments rather focus on conventional building materials stipulated in the national regulations and codes with little innovation when it comes to alternative building material. The demand for more sophisticated housing infrastructure which requires large volumes of building materials in the form of raw materials and other natural resources that are limited and non-eco-friendly are on the rise (Morel et al 2001;Jiménez Delgado and Guerrero 2007;Bachar et al 2014;Oyelami and Van Rooy 2016). If this trend would continue, natural resources will be totally depleted which may lead to environmental degradation.…”

“…Compressed earth bricks, as building material entirely satisfies the requirements of sustainable building. For a proper understanding, the word "lateritic soil" is used here to describe "the highly weathered tropical or sub-tropical residual soil with varying proportions of particle sizes ranging from clay size to gravel, usually coated with sesquioxide rich concretions with colours varying from liver brown to rusty red and "laterite" would be regarded as fitting exactly the definition but in the case of laterites, non-residual (transported) soils are often also included" (Oyelami and Van Rooy 2016).…”

Prediction of the Elastic Properties of the Clay-Rice Straw Composite by Numerical Homogenization Technique using Digimat

“…Various research projects on the Development of locally available building materials have been undertaken. In order to preserve and preserve the environment, the use of environmentally friendly building materials, commonly known as green building materials, must be promoted to promote the idea of sustainable construction [2]. One of these green building materials is adobe [3].…”