硫酸盐侵蚀下石灰石复合矿物掺合料混凝土梁抗弯性能试验研究

Experimental Study on Flexural Behavior of Limestone Compound Mineral Admixture Concrete Beam under Sulfate Attack

对经受硫酸镁溶液长期浸泡腐蚀后的石灰石复合矿物掺合料混凝土梁进行了抗弯承载力试验,对比分析了不同浸泡环境下混凝土梁的腐蚀情况、抗弯性能、变形特征和破坏形态。试验结果表明,石灰石复合矿物掺合料混凝土梁在室外环境下采用10%硫酸镁溶液浸泡300d后,发生了以石膏结晶侵蚀为主导的破坏,与在水中浸泡的混凝土梁相比,浸泡在硫酸镁溶液中的混凝土梁的抗弯性能稍有下降,开裂荷载和极限荷载略有降低,裂缝扩展速度稍快,破坏时的挠度和延性有所降低,混凝土梁在受力过程中正截面应变符合平截面假定。

The flexural behavior of limestone compound mineral admixture concrete beam eroded by magnesium sul-fate solution at long-term period was studied, and the corrosion degree, flexural behavior, deformation features and failure mode of concrete beams in different environment were analyzed. Test results show that the limestone compound mineral admixture concrete beam submerged in 10% magnesium sulfate solution after 300d in outdoor environment is broken mainly because of gypsum crystallization erosion. Compared with the concrete beam submerged in water, flexural behavior, cracking load and ultimate load of the former beam decrease slightly, the crack propagation speed grows fast as well as the deflection and ductility of the failure beams decrease. The cross section strain of concrete beam is accord with plane sec-tion assumption during the loading process.