Self-Assembling Particle-Siloxane Coatings for Superhydrophobic Concrete
Self-Assembling Particle-Siloxane Coatings for Superhydrophobic Concrete
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DOI：
10.1021/am404272v
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发表时间：
2013-12-25
影响因子：
9.5
通讯作者：
Sobolev, Konstantin
中科院分区：
文献类型：
--
作者：
Flores-Vivian, Ismael;Hejazi, Vahid;Sobolev, Konstantin
本文首次报道了一种合成疏水和超疏水混凝土的方法。混凝土通常是一种亲水材料，这大大降低了混凝土结构和路面的耐久性。为了合成拒水混凝土，制备了疏水乳液，并将其应用于硅酸盐水泥砂浆瓦上。在乳液中加入聚甲基氢硅氧烷疏水剂以及偏高岭土（MK）或硅灰（SF）来诱导微粗糙度和聚乙烯醇（PVA）纤维来形成分层表面。采用不同的混合方法研究了不同的乳液类型，并应用了单层和双层疏水涂层。采用光学显微镜和扫描电镜对乳液和涂层进行了表征，测定了乳液和涂层的润湿性能，包括水接触角（CA）和滚脱角（roll-off angle）。我们建立了一个涂层和非涂层混凝土的理论模型，该模型可以推广到其他类型的材料，用于预测表面粗糙度和成分对CA的影响。在CA值最高的地方，发现了骨料之间的优化距离。经MK基乳液处理的PVA纤维的最大CA为156。由于水渗透是导致混凝土劣化的主要因素，疏水拒水混凝土比普通混凝土具有更长的耐久性，在土木和材料工程中有着广泛的应用。
We report here, for the first time in the literature, a method to synthesize hydrophobic and superhydrophobic concrete. Concrete is normally a hydrophilic material, which significantly reduces the durability of concrete structures and pavements. To synthesize water-repellent concrete, hydrophobic emulsions were fabricated and applied on portland cement mortar tiles. The emulsion was enriched with the polymethyl-hydrogen siloxane oil hydrophobic agent as well as metakaolin (MK) or silica fume (SF) to induce the microroughness and polyvinyl alcohol (PVA) fibers to create hierarchical surfaces. Various emulsion types were investigated by using different mixing procedures, and single- and double-layer hydrophobic coatings were applied. The emulsions and coatings were characterized with optical microscope and scanning electron microscope (SEM), and their wetting properties, including the water contact angle (CA) and roll-off angle, were measured. A theoretical model for coated and non-coated concrete, which can be generalized for other types of materials, was developed to predict the effect of surface roughness and composition on the CA. An optimized distance between the aggregates was found where the CA has the highest value. The maximal CA measured was 156 for the specimen with PVA fibers treated with MK based emulsion. Since water penetration is the main factor leading to concrete deterioration, hydrophobic water-repellent concretes have much longer durability then regular concretes and can have a broad range of applications in civil and materials engineering.