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

在Walter教授的帮助下，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。Oyawa和Kiptanui博士J.A. Jomo Kenyatta University of Agriculture and Technology（乔莫·肯雅塔农业技术大学）研究结果表明：在水泥材料的替代方面，发现了大量的火山灰，其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砌块，并对当地住宅建设进行了评价。即使水泥掺量较低（约7%），SSB的强度也能达到足够的抗压强度，足以满足低层住宅的要求。特别是发现初始强度稍低，然后强度随时间增加。研究还发现，日本传统的“Donou”由塑料袋和当地土壤填充在袋子里，作为劳动力为基础的建设技术，足以在农村地区的道路基础，它可以可持续地维护当地的道路网络，以便将农产品运输到城市地区的市场。然而，目前的道路条件不太好，无法将待加工的重金属材料运输到靠近市区的地方，因此建议将工厂建在火山灰开采地附近，尽管拟议的技术适用于发展中国家，但这不能成为一项业务;即以低成本、以劳动力为基础的建筑和当地材料为基础，因此，应采用基层技术转让方法来发展东非国家的农村地区。

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.