掺多膨胀源膨胀剂复合胶凝体系的膨胀性能及力学性能研究

Study on the Expansion and Mechanical Properties of Composite Cementitious Systems with Multi-expansion Sources Expansion Agent

为研究不同膨胀源膨胀剂对复合胶凝体系膨胀性能及力学性能的影响,对单掺及复配多膨胀源膨胀剂补偿收缩复合胶凝体系的限制膨胀率及抗折、抗压强度等开展了试验研究。结果表明:氧化镁和氧化钙-硫铝酸钙(简称CA膨胀剂)两种膨胀剂在单掺情况下,CA膨胀剂膨胀量远大于氧化镁; CA膨胀剂的膨胀速率随掺量的减小而变缓,膨胀稳定期变长,而MgO膨胀剂的膨胀速率不受掺量的影响。复掺情况下,高活性MgO的限制膨胀率始终大于低活性MgO,且后期膨胀差距会随着MgO膨胀剂掺量的增加逐渐增大。当CA、MgO两种膨胀剂在质量比为1∶1复配情况下,可采用叠加原理来较为准确地预测多膨胀源膨胀剂的膨胀经时发展规律以及膨胀量。对于强度而言,相同掺量下MgO膨胀剂对强度的影响小于CA膨胀剂。此外,复掺试验组限制膨胀与限制强度随龄期发展的协调性取决于该配合比中对膨胀能贡献更大的单类型膨胀剂的协调性。

In order to study the effect of different expansion agents on the expansion properties and mechanical properties of the composite cementitious system,the confined expansion rate,flexural strength and compressive strength of the composite cementitious system with single expansion agent and multi-expansion sources expansion agent were tested.The results show that the expansive volume of the CA expansive agent is far greater than the MgO expansive agent.The expansion velocity of the CA expansive agent decreases with the decrease of the content,the expansive stabilization period is longer,while the expansion velocity of MgO expansion agent is not affected by the dosage.In the case of complex doping,the limiting expansion rate of high activity MgO is always greater than that of low activity MgO,and the later expansion gap will gradually increase with the increase of MgO expansion agent dosage.When the two expansion agents of CA and MgO are combined in a mass ratio of 1∶1,the principle of superposition can be used to accurately predict the development rule and the expansive volume of expansion agent with multi-expansion sources expansion agent.For the strength,the effect of the MgO expansive agent on the strength is lower than that of the CA expansive agent at the same content.Besides,the age-developed coherence of the confined expansion and the intensity of the composited test group is determined by the expansion agent which contributes greatly to the expansion.