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本文介绍了一种高性能混凝土膨胀剂在郑万铁路无砟轨道道床板中的应用。实验研究了这种膨胀剂的膨胀特性和微观膨胀机理。通过对道床板混凝土的结构膨胀率、混凝土试块限制膨胀率、抗压强度以及干缩的试验来确定膨胀剂在混凝土中的应用效果。试验结果证明:微膨胀混凝土限制膨胀率始终高于普通混凝土,并且干缩率较普通混凝土有较大的改善;膨胀剂的掺入对混凝土抗压强度无影响甚至略有增强;微膨胀混凝土28d以后应变值维持在70×10-6左右,而普通混凝土应变则出现负值,混凝土开裂风险较高。
This article describes the application of a high performance concrete expanders in ballastless ballast track bed of Zhengwan railway. The expansion characteristics and microscopic expansion mechanism of the expansive agent were experimentally studied. The application effect of expansive agent in concrete was confirmed by the test of the expansion coefficient of concrete of ballast bed, the limiting expansion rate, compressive strength and dry shrinkage of concrete slab. The test results show that the limited expansion rate of micro-expansive concrete is always higher than that of ordinary concrete, and the shrinkage rate is much better than that of ordinary concrete. The incorporation of expansive agent has no or even slight enhancement on the compressive strength of concrete. After the strain value remained at about 70 × 10-6, while the normal concrete strain is negative, the risk of concrete cracking higher.