INCREASE OF SCC ROBUSTNESS TO VARYING AGGREGATE MOISTURE CONTENT USING VMA
SCC is often sensitive to variations of constituent materials, and this lack of robustness is one of the main obstacles preventing SCC from becoming the mainstream cast-in-place concrete. This fact leads to substantially greater quality assurance requirement during production, increased need for manpower, and in some cases, the possibility of disrupted logistics due to rejected batches. Thus, in many cases, SCC is found to be unnecessarily costly and unreliable.The project was split into three stages, of which the first focused on mieromortar rheology,where aggregate moisture content was found to be the most important parameter affecting rheology. The second stage involved rheological measurements of concrete-equivalent mortar,based on tests conducted using different VMA types, some of which were found to increase robustness. In the third and final stage, SCC was the main focus, and here, the best performing VMAs from stage 2 were evaluated in terms of robustness relative to fresh properties. Results show that robustness can indeed be achieved using VMA, but most strikingly when the aggregate moisture content is underestimated, i.e., when the total amount of water is higher than in the mix design. It is also evident that relatively low dosages of VMA are needed to increase robustness, which is favorable in terms of relatively lower superplasticizer demand.
Peter Billberg
Swedish Cement and Concrete Research Institute
国际会议
长沙
英文
473-482
2009-06-05（万方平台首次上网日期，不代表论文的发表时间）