复掺稻壳灰/硅灰以及橡胶粉对水泥砂浆性能的影响

将原状稻壳在600℃控温煅烧,制备了高活性的稻壳灰,采用力学方法和快速冻融法分别研究了稻壳灰和硅灰的复掺比例以及橡胶粉的掺量对水泥基材料抗压强度、抗折强度以及抗冻性的影响.研究表明:随着橡胶粉掺量的不断增加,水泥基材料的抗压强度和抗折强度都有不同程度的降低,但抗冻性得到了较为明显的提高;随着稻壳灰取代硅灰比例的增加,水泥基材料的抗压强度、抗折强度都有一定程度的提高,当取代比例达到100%时,28 d抗压强度、抗折强度分别较基准组提高了15.4%和16.0%,除此之外,水泥基材料的抗冻性得到了较为明显的提高,在取代比例为100%时抗冻性达到最佳;最后,通过扫描电镜分析表明橡胶粉能够在水泥基体中引入大量封闭微小的气泡,它们是影响水泥基体抗冻性的一个很重要的因素.

Properties of cement mortar containing rice husk ash/silica fume and rubber powder

Rice husk ash with high pozzolanic activity was prepared via a temperature-controlled calcination of raw rice husks at 600℃.The relationship between the replacing rate of rice husk ash to silica fume,the rubber powder contents and the compressive strength,flexural strength and frost resistance of cement mortar were analyzed using the mechanics method and the quick frost method.The results showed that the compressive strength and flexural strength of cement mortar decreased in different degrees with increasing contents of rubber powder,while the frost resistance was significantly improved.When increasing the replacing rate of rice husk ash to silica fume,the compressive strength and flexural strength of cement mortar enhanced to a certain extent,and as it reaches to 100%,they increased by 15.4%and 16.0%respectively compared with the reference group after curing for 28 days,in addition,the frost resistance of cement mortar obviously enhanced as well.Finally,The scanning electron microscope analysis showed that the rubber powder can introduce a large amount of tiny closed bubbles into the cement mortar,which acted as an important factor on the frost resistance of cement mortar.