原位纳米SiO2防护剂对水泥砂浆防护效果的试验研究

为阻止空气中CO2渗入混凝土以提高其耐久性能,在试件表面采取涂刷由正硅酸乙酯(TEOS)、乙醇和水配制成的纳米SiO2防护剂的方法,待充分反应后,测试试件吸水率和碳化深度并对试件横断面进行显微硬度检测。试验结果表明:1)不同配合比的防护剂均可降低砂浆吸水率和碳化深度,当防护剂配比为乙醇∶水∶TEOS=4∶1∶3时防护效果最明显,其中吸水率可降低73%,碳化深度至少降低50%;2)根据显微硬度以及碳化试验结果,试件表层硬度随着防护剂的渗入逐渐提高,其有效作用深度为1 mm-2 mm。结论是原位纳米SiO2防护剂可用于混凝土表层防护,可提高结构的耐久性。

Research on Protective Effect of In-situ Nano-SiO2 Protective Liquid on Cement Mortar

In order to prevent CO2 in the air from infiltrating into the concrete and improve its durability,the specimen surface was coated with Nano-SiO 2 protective agent made of ethyl orthosilicate(TEOS),ethanol and water.After the reaction was completed,the water absorption and carbonization depth of the specimen were tested,and the cross-section of the specimen was tested for microhardness.The test results show that:1)protective agents of different mixture ratio can reduce the water absorption rate and carbonization depth of mortar,when the ratio of protective agents is ethanol:water:TEOS=4∶1∶3,the protective effect is the most obvious,which can reduce the water absorption rate by 73%,carbonization depth by at least 50%;2)according to the microhardness and carbonization test results,the surface hardness of the specimen increases gradually with the penetration of protective agent,and its effective depth of action is 1mm-2mm.The conclusion is that in situ Nano-SiO2can be used to protect the surface of concrete and improve the durability of the structure.