土壤混合水泥工程性質之研究

Abstract

以土壤是否適合當作混凝土細骨材來使用？為本研究之主要動機。一般混凝土配比設計用水灰比來控制，是一種最佳的配比設計方法。但混凝土水灰比與土灰比有相依線性關係，為了方便比較各固定比例水泥與土壤，混合而成土壤混合水泥的工程性質，利用此種水灰比與土灰比相依關係，本研究某些部分嚐試用土灰比來設計。另亦觀察得抗壓強度與流度沒有絕對關係，抗壓強度與流度互為獨立，但流度值會調整土灰比與水灰比相依關係，即每一種土壤，每一個流度，有一種抗壓強度與土灰比之關係。 土壤混合水泥土灰比（S/C值）在 9 至 4 間，土壤混合水泥抗壓強度增加速率緩慢，並且所增加的強度不多。S/C值小於 4 以後，強度增加速率甚快，強度可達 300 ~ 400kg/cm2附近。但 s/c=0.25~0.11時，土壤混合水泥強度與水泥砂漿很接近。 本研究發現土壤混合水泥的抗拉與劈裂強度很低，並且水泥含量高低，對抗拉與劈裂強度的影響有限。土壤混合水泥之滲透係數隨水泥含量之增加而降低，所以土壤混合水泥很適合做為止水材料，如壩心，邊坡…等。土灰比愈大，則有較大之乾縮量。隨著土灰比的增加，其不論在初凝或終凝時間均往後延遲。土灰比愈小，彈性模式愈大。 目前水庫淤積之泥砂都藉由抽取方式加以清除，但於泥的活性很高，抽取後之棄置問題確給管理機關帶來相當大之困擾，本研究建議可利用土壤混合水泥穩定原理，於淤泥加入水泥處理，先將淤泥活性降低，以方便來日的清運工作。

The purpose of the paper are to use soil as fine aggregates and study theirs properties of engineering. The water-cement ratio is the best of propertion design for concrete. Because soil-cement ratio depend linearly on water-cement ratio for concrete, this reserch for engineering properties of soil-cement mixture try design to utilize soil-cement ratio. It is convenience that propertion give to stationary propertion of soil-cement mixture. To observe that flow relate to compressive strength independent, but flow value adjust soil-cement ratio and water-cement ratio of relation of linear dependent. When soil-cement ratio of soil-cement mixture are 9 to 4, compressive strength of soil-cement are gradually increase and little differ. The value of soil-cement ratio exceed 4, then development speed of compressive strength is guickly grow to reach to 300~400kg/cm2 The compressive strength of soil-cement mixture egual to that of cement mortars, while soil-cement ratio is 0.25 to 0.11. The result of research indicates that tensile and splitting tensile strength of soil-cement are very low and increase cement to change tensile and splitting tensile of strength si little. So soil-cement mixture are properly waterproof materials as dam. slope etc, permeability coefficient is reduced by content of soil-cement ratio is retard. The dry shrinkage is growth, if soil-cement ratio is increase. Soil-cement ratio is increase, then time of setting is late. When soil-cement ratio is decrease, modulus of elasticity is more large. Reservior pump sedimentation from bottom of dam, but it is difficult that sedimentation is handle and management. A suggestion of ous study to apply principle of soil-cement mixture put cement in sedimentation in order to descend vigorous, then this easy to eliminate and transportation task.