Experimental study on mortar with the addition of hydrophobic silicone oil for water absorption, strength, and shrinkage
Experimental study on mortar with the addition of hydrophobic silicone oil for water absorption, strength, and shrinkage
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DOI：
10.1016/j.conbuildmat.2023.130323
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发表时间：
2023-02
影响因子：
7.4
通讯作者：
Y. Luan;S. Asamoto
中科院分区：
文献类型：
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作者：
Y. Luan;S. Asamoto
在这项研究中，硅油的疏水剂被用来处理砂浆，通过直接混合到混合物中，并将其喷洒在砂上进行预处理，分别旨在提供砂浆的体积拒水性，即使发生开裂也可以持续。接触角测量表面润湿性，并在两种不同条件下预干燥的声音试样上测试吸水性和氯化物渗透。对预开裂的试样进一步测试吸水性以表征具有裂纹的防水性。还测试了砂浆的抗压强度、杨氏模量、干燥和自生收缩以及凝固时间。结果表明，随着掺量和喷洒量的增加，砂浆的吸水率和氯离子渗透率均比未处理砂浆显著降低。此外，对于预开裂的试样，吸水率显着低于未处理的砂浆，特别是在润湿/干燥循环，表明即使发生裂缝，也可以在一定程度上保持体积防水性。另一方面，硅油降低了两种处理的抗压强度和杨氏模量。与未处理的砂浆相比，自收缩和干燥收缩倾向于降低。对于直接搅拌，减少干燥收缩的部分原因是其比未处理的砂浆的水损失少，而对于喷砂，削弱ITZ的砂浆被推断在减少干燥和自生收缩中发挥主要作用。
In this study, a hydrophobic agent of silicone oil was used to treat mortar by directly mixing into the mixture and spraying it on the sand for pre-treatment, respectively, aiming to offer the mortar bulk water repellency that can be sustained even on the occurrence of cracking. Contact angle was measured for surface wettability, and water absorption and chloride penetration were tested on sound specimens that were pre-dried under two different conditions. Water absorption was further tested on the pre-cracked specimens to characterize water repellency with cracks. The mortar was also tested for compressive strength, Young’s modulus, drying and autogenous shrinkage as well as setting times. The results indicated significant reduction of water absorption and chloride penetration with increasing addition and spraying amount of the agent than those of untreated mortar. Furthermore, for the pre-cracked specimens, water absorption was remarkably lower than that of untreated mortar, particularly under wetting/drying cycles, indicating that bulk water repellency can be preserved at a certain degree even if cracks occur. On the other side, the silicone oil reduced compressive strength and Young’s modulus for both treatments. Autogenous shrinkage and drying shrinkage tended to decrease compared to untreated mortar. For direct mixing, the reduced drying shrinkage was partially attributed to its less water loss than that of untreated mortar, whereas for sand spraying, the weakened ITZ of the mortar was inferred to play a major role in reducing drying and autogenous shrinkage.