丁苯乳液改性混凝土的力学性能及抗冻性能的实验分析

Experimental Analysis of Mechanical Properties and Frost Resistance of Styrene-butadiene Emulsion Modified Concrete

研究了丁苯乳液对改性混凝土工作性能、力学性能和抗冻耐久性能的影响。实验结果表明,随着聚灰比的增加,坍落度呈非线性递增趋势,丁苯乳液(SBR)可改善混凝土的流动性;同一养护龄期下,混凝土的抗折强度随着聚合物掺量增加而增加,但抗压强度有所降低。冻融循环试验表明,同一冻融循环次数下,质量损失率随着丁苯乳液掺量的增加而逐渐降低,在经历75次冻融循环后,聚灰比15%和聚灰比20%的改性混凝土质量损失率较基准混凝土分别下降了67%和70%,改性后的抗剥落能力有很大提升,但冻融循环后各试块的抗压强度均有所下降,因此,在工程中运用改性混凝土时应考虑丁苯乳液对其抗冻性能的影响。

This paper studies the effect of styrene-butadiene emulsion(SBE) on the working performance,mechanical properties and frost resistance durability of modified concrete. The experimental results show that the slump presents a non-linear increasing trend with the increase of the polymer-to-cement ratio. SBE can improve the fluidity of concrete. At the same curing age, the flexural strength of concrete increases with the increase of the amount of polymer while the compressive strength decreases. The freeze-thaw cycle test shows that with the same number of freeze-thaw cycles, the mass loss rate gradually decreases with the increase of the amount of styrene-butadiene emulsion. After 75 freeze-thaw cycles, it is found that compared with the benchmark concrete, the mass loss rates of the modified concrete with the poly-ash ratio 15 % and 20 % drop by 67 % and 70 % respectively. After the freeze-thaw cycle, the anti-stripping ability after modification improves greatly whereas the compressive strength of each testing block decreases. Therefore, the influence of styrene-butadiene emulsion on its frost resistance should be taken into consideration when modified concrete is used in the project.