自密实钢纤维全轻混凝土的收缩性能试验研究

发布时间：2018-09-10 20:19

【摘要】：自密实钢纤维全轻混凝土是在自密实全轻混凝土中加入一定量乱象分布的钢纤维后形成的一类新型复合材料。本文对自密实钢纤维全轻混凝土的早龄期抗裂性能、自收缩和干燥收缩性能的研究现状、影响因素等进行探讨,并通过试验研究分析自密实钢纤维全轻混凝土的早龄期抗裂性能、自收缩和干燥收缩性能。试验在课题组已有试验基础上选取混凝土强度等级C40,选取的试验参数为钢纤维掺量和粗骨料最大粒径。钢纤维体积率在0%~1.6%范围内按0、0.8%、1.2%、1.6%掺加,研究不同的钢纤维掺量对自密实钢纤维全轻混凝土早龄期抗裂性能和试件裂缝状态变化以及对自收缩和干燥收缩的影响。选取粗骨料最大粒径分别为10mm、16mm和20mm,通过试验研究不同粗骨料最大粒径对自密实钢纤维全轻混凝土早龄期抗裂性、自收缩和干缩的影响。结果表明,在早龄期抗裂试验中,自密实钢纤维全轻混凝土在前1.5d内裂缝发展速度较快,1.5d之后发展速度趋于平缓。早龄期抗裂性能随着钢纤维掺量的增加而提高;当粗骨料最大粒径为16mm、钢纤维掺量1.2%时,混凝土的早龄期名义裂缝面积和裂缝深度都达到最小,抗裂等级也要高于粗骨料最大粒径为10mm和20mm的混凝土。随着钢纤维掺量增加,自收缩值逐渐减小。在骨料最大粒径10mm、钢纤维掺量1.2%时,自收缩值最小。当钢纤维掺量在0%到1.2%范围内时,干燥收缩随着钢纤维掺量的增加而减小,当掺量增大到1.6%,收缩值降低不明显。骨料最大粒径为16mm时,干燥收缩值达到最小。最后综合分析试验数据,对试验实测数据进行拟合,相关性系数R均大于0.9,拟合度较好。将拟合值与实测值进行对比,得出拟合度良好的拟合曲线。
[Abstract]:Self-compacting steel fiber all-light concrete is a kind of new composite material formed by adding a certain amount of disordered steel fiber to the self-compacting total light concrete. In this paper, the early age crack resistance, autogenous shrinkage and drying shrinkage of self-compacting steel fiber all-light concrete are discussed, and the influencing factors are also discussed. The early age crack resistance, autogenous shrinkage and drying shrinkage of the self-compacting steel fiber whole light concrete were analyzed by experiment. The concrete strength grade C40 is selected on the basis of the existing tests in our research group. The test parameters are steel fiber content and maximum particle size of coarse aggregate. The volume ratio of steel fiber in the range of 0% and 1.6% is 0.8% and 1.2% and 1.6% respectively. The effects of different content of steel fiber on crack resistance and crack state of self-compacting steel fiber whole light concrete at early age and on autogenous shrinkage and dry shrinkage are studied. The maximum diameter of coarse aggregate is 10mm / 16mm and 20mm respectively, and the effects of maximum diameter of coarse aggregate on the early age crack resistance, autogenous shrinkage and dry shrinkage of self-compacting steel fiber whole light concrete are studied by experiments. The results show that, in the early age crack resistance test, the crack development rate of the self-compacting steel fiber fully light concrete in the first 1.5 days is faster than that in the first 1.5 days, and the development speed tends to be gentle after 1.5 days. When the maximum diameter of coarse aggregate is 16mm and the content of steel fiber is 1.2, the nominal crack area and crack depth of concrete at early age reach the minimum. Crack resistance grade is also higher than the coarse aggregate maximum particle size of 10mm and 20mm concrete. With the increase of steel fiber content, the self-shrinkage value decreases gradually. When the maximum diameter of aggregate is 10 mm and the content of steel fiber is 1.2 mm, the value of autogenous shrinkage is the smallest. When the content of steel fiber is in the range of 0% to 1.2%, the drying shrinkage decreases with the increase of the content of steel fiber, but the shrinkage value does not decrease obviously when the content of steel fiber increases to 1.6%. When the maximum particle size of aggregate is 16mm, the drying shrinkage value reaches the minimum. Finally, the experimental data are analyzed synthetically, and the experimental data are fitted. The correlation coefficient R is greater than 0.9, and the fitting degree is better. The fitting curve with good fitting degree is obtained by comparing the fitting value with the measured value.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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