摘要
通过室内夯实水泥土桩无侧限抗压强度实验和微观结构观测,研究了击实水泥土强度随养护龄期增长的微观机理.实验结果表明:随养护龄期的增长,击实水泥土块的无侧限抗压强度增加,渐趋于一个稳定值;60d龄期强度即可作为击实水泥土的设计强度.水泥土强度随龄期增长实质上反映了水泥水化凝胶体与拌和土料中的活性物质之间的离子交换和团粒化作用,以及硬凝反应程度由弱变强,在微观结构上表现为水泥土块中水化物结晶体由絮状、纤维状结构逐渐变为菊花状结构,最终形成网格状结构;粒间孔隙由大变小,分散状的土颗粒发生团粒化,随着水化作用的持续进行,相邻团粒被网格状水化物晶体联接形成水泥土结石体,从而导致水泥土强度的提高.
The micromechanism of strength increase with curing time for compacted cement-soil was investigated by unconfined compressive strength experiment and microstructure observation. The results show that the unconfined compressive strength increases with increasing curing time, and the extent of the strength gradually decreases and then tends to steady. The strength of 60 d curing time can be used for engineering design of compacted cement soil. The change in strength with curing time substantively is cement hydration from weak to strong, ion exchange and agglomeration between hydrated gelatin and active substance of mixed soil, and induration reaction. The microstructure of hydrated crystals is from floccule and fibre-like to mum-like, finally to gridding. The pore among grains is from large to small. Cement hydration makes dispersed soil grains to agglomerate. With durative cement hydration, soil and hydrated substance agglomerations join each other to form cement-soil concretion by gridding hydrated crystals, which results in the increase of cement-soil strength.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2008年第3期233-238,共6页
Journal of University of Science and Technology Beijing
基金
河北省交通厅基金资助项目(NoY060236)
关键词
水泥土
击实
无侧限抗压强度
微观结构
养护龄期
cement soil
compact
unconfined compressive strength
microstructure
curing time
