研究了用不同体积掺量(0%,50%,100%)页岩陶粒取代普通骨料配制的不同水胶比混凝土的应力一应变关系,以及混凝土内部水泥石和骨料的弹性模量与显微硬度,同时对砂浆和混凝土强度之间的发展关系进行了分析,力图探讨页岩陶粒对混凝土破坏特征及机理的影响.结果表明,随页岩陶粒掺量的增加,混凝土应力-应变全曲线的上升段斜率变小,下降段的坡度变缓,破坏形式也由斜截面剪切转为纵向劈裂;页岩陶粒的掺入使得混凝土内部骨料与水泥石的界面区得到改善,骨料与基体的显微硬度更为接近,弹性更为协调;在普通混凝土中掺入部分页岩陶粒,当砂浆强度较低时,陶粒周围增强的界面区以及与砂浆较为良好的弹性协调在一定程度上弥补了陶粒自身对混凝土强度的不利影响,混凝土破坏主要取决于砂浆强度;但当砂浆强度较高时,低强度的陶粒会在一定程度上会降低混凝土的强度,但陶粒的"自养护"作用对混凝土后期强度增长有利.
Normal weight aggregate (NWA) was replaced by shale ceramsite with different volume ratios of 0% , 50% and 100%. The influence on stress-strain curve of concrete with different water-to-binder ratios and elastic modulus as well as the microhardness of mortar and aggregate in concrete were investigated. The strength development relationship between mortar and concrete was analyzed. Results show that, with the increase of shale ceramsite content, the upward slope of concrete stress-strain curve is reduced, the grade of descending branch becomes gentle, and the concrete is destructed from oblique shearing to longitudinal splitting. Due to the addition of shale ceramsite, the difference of microhardness and elastic modulus between aggregate and cement paste is reduced and the interfacial zone between them is improved. When mortar strength is low, the failure of combined aggregate concrete mainly depends on mortar which is account for the strong interfacial zone around ceramsite and the good elasticity harmony between ceramsite and mortar. When mortar strength is high, the low particle strength of ceramsite will limit the development of concrete strength, however the internal curing effect of ceramsite is helpful to the increase of concrete long-term strength.
参考文献
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