Investigation on Alternative Cement Materials in East Africa and Their Sustainable Supply Methodology

在乔莫肯雅塔农业科技大学的Walter， O. Oyawa教授和Kiptanui J.A. Too博士的帮助下，以东非的肯尼亚为重点，对替代水泥材料及其在民用基础设施建设中的应用进行了调查。得到以下结论。在替代水泥材料方面，发现了大量的灰火山灰，替代普通水泥的可能性很大。然后，将火山灰水泥与当地土壤混合制成稳定土块，并对其进行评价，用于当地住宅建设。即使水泥掺量较低（约7%），SSB的抗压强度也足以满足低层住宅建筑的要求。特别是发现初始强度略低；然后，强度随时间增加。研究还发现，日本传统的用塑料袋制作的“多努”和当地填埋的土壤，作为以劳动力为基础的施工技术，足以在农村地区制作道路基础，可以持续维护当地的道路网络，以便将农产品运输到城市市场。但是，目前的道路条件不太好，不适合在靠近市区的地方运输要加工的重胶凝材料，因此建议工厂选址在靠近火山灰矿区的地方。尽管拟议的技术适合发展中国家，但这不能成为一项业务；即以低成本、劳力为主的建筑和当地材料为基础，以便在发展东非国家农村地区时采用基层技术转让方法。

The investigation on alternative cement materials and their application to civil infrastructure construction was carried out by focusing Kenya in East Africa, with helpful assistance from Prof Walter, O. Oyawa and Dr. Kiptanui J.A. Too of Jomo Kenyatta University of Agriculture and Technology. The following conclusions are obtained.As for the alternative cement materials, the large amount of pozzolana which may have high possibility to replace the ordinary cement were found. Then, the stabilized soil blocks made of mixing the pozzolanic cement and local soils were made and assessed for local housing construction. Even though the low amount of cement mixed with pozzolana, about 7%, the strength of SSB can have enough compressive strength which was enough for low rise housing construction. Particularly it was found that the initial strength was a little low; then, the strength increased with time. It was also found that the Japanese traditional "Donou" made of plastic bags and local soils filled in the bag are good enough to made road foundation in rural area as labor-based construction technology, which can sustainably maintain the local road network in order to transport agricultural products to the market in urban area. However, the current road condition is not so good to transport the heavy cementious materials to be process somewhere near urban area, so that it was recommended the factory should be located close to the mining place of pozzolana.Even though the proposed technology is suitable for developing countries, this cannot be a business; that is, based on low cost, labor-based construction and local material, so that grass roots technology transfer methodology should be employed for developing the rural area of East African countries.