Factors Affecting Use of Appropriate Building Materials and Technologies
Introduction:
This research project examines Appropriate Building Materials and Technology , which has been popularized in Kenya for well over thirty years apparently without meeting the desired results of exponential increase in uptake of its products among the target population. It first examines the rationale and need for AT in construction generally and in Kenya in particular. It then looks at the prevalence of factors that have contributed to the adoption of the technology on the one hand and those that have inhibited its growth on the other hand.
The study utilizes the Compressed Stabilized Earth Blocks (CSEB), one of the best-known products of AT locally to demonstrate the kind of challenges the technology has encountered in the Kenyan context. It discusses literature pertaining to the materials under study starting from the global to the local context, giving an understanding of the material itself and its merits and demerits. The literature also gives a pointer as to the likely areas to be examined in the local context to be able to pinpoint weak points to sustained growth in the use of CSEB.
General Information on Appropriate Building Materials in Developing Countries:
UNCHS (1985) indicates the importance of building materials sector as regards to national development in the developing countries. They are used in the construction of all capital projects i.e. roads, railways, harbours, bridges, dams, factories and other building and civil engineering infrastructure works on which the rest of the national economies depend accounting for about 80% of total capital assets in developing nations. Construction of shelter provides a place of abode for labour and also space for manufacturing of goods and offering of services essential to the economies.
Literature Pertaining to the Need for Appropriate Building Materials and Technologies:
According to the Kenyan Vision 2030, Kenya will be a predominantly urban country by year 2030 if the current demographic trends hold true, and envisages an adequately and decently housed populace by 2020 in what is called a „sustainable environment‟. Accordingly, the annual production of housing units from 35,000 in 2010 to over 200,000 by 2012. It proposes a planning and development starting with cities and towns while concurrently catering for the rural settlements.
Suitability tests of soils for CSEB making:
In selecting a suitable soil, optimizing the soil mix, and evaluating strength, deformability. The procedure is a systematic series of processes evaluating potential soils at every phase of production. Readily available potential soils are classified and then methodically evaluated through the sequence of tests.
If at any point during the process, the proposed soil or soil mixture does not satisfactorily satisfy the requirements, a step back is taken to reconsider further action through selection of a new soil or soil amendments.
Soil classification:
A grain size analysis is required to classify a soil. A proper classification will correctly identify a soil, thus providing insight to the soil’s properties. Soils are tested and classified as per the Unified Soil Classification System – USCS. Clay and silt are commonly referred to as fine grained soils, while sand and clay are referred to as coarse grained soils.
Dry Soil Grain Size Analysis:
For coarse grained soils, a grain size analysis is performed by shaking a raw soil sample in a Gilson Testing Screen Model. Samples are first air-dried for several days to achieve maximum separation during sieving.
Selection of Soil Mix Ratios:
The soils to be used for SCEB production contain primarily angular sand, clay and silt. Larger aggregate particles such as gravel and rocks may also be present in the mined soil and are typically removed by screening. Soil samples vary widely from region to region and the composition of the samples from one site may also vary.
Advantages of CSEB Technology as a subset of Appropriate Building Materials and Technology:
The motivation of this research is the standardization need for widespread use of earth as an alternative building material. Concrete has grown into the most important building material over the last century and in industrialized nations the annual production amounts to 1.5-3 tons per capita. The use of cement in the production of concrete contributes vastly to the construction industry’s carbon footprint.
Criticism of Appropriate Building Materials And Technology:
According to Willoughby the criticisms could be grouped into those that concern the ideals and claims of the Appropriate Technology movement on the one hand and those that raise fundamental questions as to the validity of appropriate technology per se on the other hand. The former he terms “general” and the latter as “political”.
Conclusion:
The conclusions emanating from this study relate to the objectives which were included viz-: establishing the factors affecting the adoption of Compressed Stabilized Earth Block (CSEB) technology in the Kenyan context; identification through situation analysis of the construction industry in Kenya the stakeholders of CSEB and their role in adoption appropriate technology (AT) and recommending practical solutions that can be taken to foster the adoption of AT for building solutions in Kenya.
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