Chen Chi-Yao, Shen Zih-Yao, Lee Maw-Tien
Department of Applied Chemistry, National Chiayi University, Chiayi City 600355, Taiwan.
Materials (Basel). 2021 Jul 1;14(13):3687. doi: 10.3390/ma14133687.
It is well known that most cement matrix materials are hydrophilic. For structural materials, hydrophilicity is harmful because the absorption of water will induce serious damage to these materials. In this study, crumb rubber was pretreated by partial oxidation and used as an additive to develop a hydrophobic rubberized cement paste. The pretreated crumb rubber was investigated using Fourier-transform infrared spectrometry (FT-IR) to understand the function groups on its surface. The pyrolysis oil adsorbed on the surface of the crumb rubber was observed by FT-IR and nuclear magnetic resonance (NMR) spectroscopy. A colloid probe with calcium silicate hydrate (C-S-H) at the apex was prepared to measure the intermolecular interaction forces between the crumb rubber and the C-S-H using an atomic force microscope (AFM). Pure cement paste, cement paste with the as-received crumb rubber, and cement paste with pretreated crumb rubber were prepared for comparison. FT-IR, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to understand the microstructure of the pastes. The static contact angle was used as the index of the hydrophobicity of the pastes. Experimental results showed that the hardened cement paste containing partially oxidized crumb rubber had excellent hydrophobic properties with an insignificant reduction in the compressive strength.
众所周知，大多数水泥基材料都是亲水的。对于结构材料而言，亲水性是有害的，因为吸水会对这些材料造成严重损害。在本研究中，通过部分氧化对胶粉进行预处理，并将其用作添加剂来制备疏水性橡胶化水泥浆体。使用傅里叶变换红外光谱仪（FT-IR）对预处理后的胶粉进行研究，以了解其表面的官能团。通过FT-IR和核磁共振（NMR）光谱观察吸附在胶粉表面的热解油。制备了顶端带有硅酸钙水合物（C-S-H）的胶体探针，以使用原子力显微镜（AFM）测量胶粉与C-S-H之间的分子间相互作用力。制备了纯水泥浆体、含有未处理胶粉的水泥浆体和含有预处理胶粉的水泥浆体进行比较。使用FT-IR、X射线衍射（XRD）和扫描电子显微镜（SEM）来了解浆体的微观结构。将静态接触角用作浆体疏水性的指标。实验结果表明，含有部分氧化胶粉的硬化水泥浆体具有优异的疏水性能，抗压强度降低不显著。
