摘要
泡沫轻质土作为一种新型的轻质填料,目前被广泛用于软土地基处理、道路加宽与桥台台背回填等方面。为了改善泡沫轻质土的性能,采用偏高岭土等量取代水泥,通过正交试验提出了偏高岭土泡沫轻质土最优配合比,并通过试验探讨了不同胶凝材料用量、偏高岭土掺量以及水胶比对轻质土抗压强度的影响规律,进一步对其干缩、干湿循环、抗冻性能及微观形貌进行了试验研究,最后确定了其初步最佳配合比。结果表明:泡沫轻质土抗压强度影响因素的显著性大小为:偏高岭土掺量>胶凝材料用量>水胶比;随水胶比的增大,其各龄期干缩率减小,而其干湿循环及冻融循环后的抗压强度损失率逐渐减小;随偏高岭土掺量增加,其各龄期干缩率先减小后增大,当其掺量为20%时干缩率最小,而其干湿循环及冻融循环后的抗压强度损失率逐渐增大;综合各性能得到偏高岭土泡沫轻质土最佳配合比为:水泥∶偏高岭土∶发泡剂∶水=1∶0.25∶0.025∶0.69。随着偏高岭土掺量的增加,试件内部偏高岭土易发生团聚、大气泡数量增加,导致结构密实度较差,不利于强度的发展。
At present,foamed cement banking(FCB)as a new type of lightweight filler,which has been widely used in soft soil foundation treatment,road widening,bridge abutment back backfilling etc.In order to improve the properties of foamed cement banking,the cement is replaced by abundant metakaolin,the optimal mixture ratio of FCB with metakaolin were proposed by orthogonal experiments,the effects on compressive strength of FCB of different cementitious material content,the metakaolin content,water binder ratio were studied,and the drying shrinkage,dry wet cycle and frost resistance were studied.Finally,the initial optimum mix ratio was determined.The results show that the significant factors influencing the compressive strength of FCB are from large to small,metakaolin content,cementitious material content,water binder ratio.With the increase of water cement ratio,the each age shrinkage rate decreases,after the dry wet cycling and freeze-thaw cycle the compressive strength loss rate gradually decreases.With metakaolin dosage increasing,dry shrinkage first decreases and then increases the age,metakaolin content 20%the shrinkage rate of the minimum,after the dry wet cycling and freeze-thaw cycle the compressive strength loss rate gradually increased.The initial optimum mix ratio of FCB is that the cement∶kaolin∶foaming agent∶water is 1∶0.54∶0.03∶0.85 was obtained.With the increase of the content of metakaolin,the agglomeration of metakaolin is easy to occur in the specimen,and the number of bubbles increases,which leads to poor structure compactness and is not conducive to the development of strength.
作者
孙赛炜
刘勇
陈伟
何倍
关宏信
高英力
SUN Saiwei;LIU Yong;CHEN Wei;HE Bei;GUAN Hongxin;GAO Yingli(Baotou Highway Engineering Quality Supervision Station,Baotou 014030,China;Baotou Highway Engineering Company Ltd.,Baotou 014030,China;School of Traffic and Transportation Engineering,Changsha University of Science&Technology,Changsha 410114,China)
出处
《混凝土》
CAS
北大核心
2020年第1期95-99,共5页
Concrete
基金
国家自然科学基金项目(51978080)
国家自然科学基金委员会与中国民用航空局联合资助项目(U1833127)
湖南省自然科学基金项目(2018JJ4016)
湖南省教育厅科学研究重点项目(18A129)
关键词
偏高岭土
泡沫轻质土
配合比
性能
试验
Kaolin
foamed cement banking
mixture ratio
performance
experiment
