西非混凝土骨料碱含量试验与质量控制技术研究  

Research on Alkali Content Test and Quality Control Technology of Concrete Aggregates in West Africa

作　　者：夏利军 XIA Lijun(China Civil Engineering Construction Corporation,Beijing 100038,China)

机构地区：[1]中国土木工程集团有限公司,北京100038

出　　处：《铁道建筑技术》2023年第9期194-198,共5页Railway Construction Technology

基　　金：中国土木工程集团有限公司科技研究开发计划项目(ZT-2021B03)。

摘　　要：以西非尼日利亚拉各斯至伊巴丹铁路为研究背景,运用室内试验的手段对料场的花岗岩骨料进行X光射线衍射图谱试验、骨料碱活性试验及碱骨料反应抑制试验研究。结果表明,各组花岗岩试样的主要成分为石英、高岭石、伊利石、钾长石和钠长石,石英、钠长石、钾长石的相对强度峰值较多,伊利石次之,高岭石最少;伊利石和钠长石含量较高,介于25%~50%之间,石英和钾长石的含量次之,介于10%~20%之间,高岭石的含量最低,均≤5%;Na_(2)O和K_(2)O的溶出量均随时间呈近对数曲线的变化趋势,大于60 d后,Na_(2)O和K_(2)O的溶出量均变化较小;改进UMPC方法得到的Na_(2)O溶出量约为水浸出法的15~21倍,K_(2)O溶出量约为水浸出法的4~16倍;砂浆棒试件在养护28 d时,砂浆棒试件膨胀率达到0.38%,具备典型的碱-硅酸反应特征,花岗岩骨料具有潜在碱集料反应活性;施工时,可采用“Lafarge水泥+15%Ⅰ级粉煤灰”或“Dangote水泥+25%Ⅰ级粉煤灰”的策略进行花岗岩骨料的碱集料反应抑制,以达到良好的混凝土质量控制效果。Taking the Lagos-Ibadan Railway in Nigeria,West Africa as the research background,laboratory tests were conducted to study the X-ray diffraction pattern,aggregate alkali activity,and alkali aggregate reaction inhibition of granite aggregates.The results show that the main components of each group of granite samples are quartz,kaolinite,illite,K-feldspar and albite.The relative strength peaks of quartz,albite and K-feldspar are more,followed by illite and kaolinite;the content of illite and albite is relatively high,ranging from 25%to 50%,followed by quartz and potassium feldspar,ranging from 10%to 20%,and the content of kaolinite is the lowest,both≤5%;the dissolution amounts of Na_(2)O and K_(2)O show a nearly logarithmic trend over time,and after more than 60 days,the dissolution amounts of Na_(2)O and K_(2)O show a small change;the Na_(2)O leaching amount obtained by improving the UMPC method is about 15-21 times that of the water leaching method,and the K_(2)O leaching amount is about 4-16 times that of the water leaching method;after 28 days of curing,the expansion rate of the mortar bar specimen reached 0.38%,exhibiting typical alkali-silica reaction characteristics.Granite aggregate has potential alkali aggregate reaction activity;during construction,the strategies of“Lafarge cement+15%Grade I fly ash”or“Dangote cement+25%Grade I fly ash”can be used to suppress the alkali aggregate reaction of granite aggregates,in order to achieve good concrete quality control effect.

关 键 词：混凝土骨料 西非 碱含量试验 尼日利亚拉伊铁路 碱骨料反应 X射线衍射图谱 碱活性 

分 类 号：TU528.041[建筑科学—建筑技术科学]