混掺纤维对改善活性粉末混凝土弯曲韧性的试验研究  

Experimental study on the hybrid fiber to improve the flexural toughness of reactive powder concrete

作　　者：邓宗才[1] 周冬至[1] Jumbe R.Daud 

机构地区：[1]北京工业大学城市与工程安全减灾省部共建教育部重点实验室,北京100022

出　　处：《混凝土》2014年第4期90-92,96,共4页Concrete

基　　金：国家自然科学基金(51378032)

摘　　要：通过钢纤维与高性能合成纤维混掺以改善活性粉末混凝土的韧性、降低脆性，由弯曲试验测得了荷载～位移曲线，分析了钢纤维与不同品种、不同掺量合成纤维混掺对改善RPC韧性的效果。试验发现：当钢纤维体积掺量1％或2％与粗聚烯烃纤维或细聚乙烯醇纤维混掺时，可显著改善RPC的弯曲韧性；首次实现了使RPC变形具有“二次硬化”特征；钢纤维体积掺量为1％，与粗聚烯烃纤维、细聚乙烯醇纤维混掺时的韧性指标T（5）和T（7）比单掺钢纤维时分别提高49．8％～140％和82．3％～215．6％；从经济性看，钢纤维掺量为1％与粗聚烯烃或者细聚乙烯醇纤维混掺时，其增韧效果更优；钢纤维掺量为2％时，细聚乙烯醇纤维掺量不宜高于9kg／m^3。Steel fiber combined with high performance synthetic fibers were used to improving toughness and reduce brittleness of reac-tive powder concrete （RPC） herein.Load-displacement curves were obtained by the flexural toughness experimental.The toughness im- proving effects of steel fibers combined with synthetic fibers for RPC were researched.From the test results, it is found that：when the vol ume dosage of steel fiber is 1% to 2% and mixed with either macro-polyolefin fiber or micro polyvinyl alcohol （PVA） fiber, the flex-ural toughness of RPC can be significantly improved;from the load-displacement curves it is observed that deformation of the RPC speci-mens is able to achieve second-hardening characteristics （strain hardening performance ）;Comparing to specimens with only 1% steel fibers, the toughness index of specimens combined with 1% steel fibers and macro-polyolefin fiber or miero-polyvinyl alcohol fiber was in-creased by about 49.8%-140% and 82.3%-215% respectively.The most economical dosage of steel fibers dosage with the best effect on the toughness of RPC ; when steel fiber content is 2%, the fine PVA fiber dosage should not be more than 9 kg/m^3.

关 键 词：活性粉末混凝土 混掺纤维 弯曲韧性 二次硬化 

分 类 号：TU528.041[建筑科学—建筑技术科学]