There are essential differences between recycled brick aggregate (RBA) and recycled concrete aggregate (RCA). The weak area of RCA is the old mortar attached to the aggregate surface, while the weak area of RBA is its own larger porosity. Silane has a small molecular structure, which can penetrate into the concrete with water as the medium and react with the active functional groups in the concrete to form a network structure of silane polymer. In this paper, 8% silane solution was used to modify recycled brick aggregate concrete (RBAC) in two schemes. The first scheme was that RBA was soaked in 8% silane solution, and the second scheme was that 8% silane solution was added in the mixing process of RBAC instead of water. The results showed that compared with the unmodified RBA, after silane modification of RBA its apparent density increased by 5.48%, water absorption decreased by 61.12%, crushing index decreased by 11.09%. The average compressive strength of RBAC with RBA modified by silane was 11.72% higher than that of unmodified RBAC, and the average compressive strength of RBAC mixed with silane was 9.12% lower than that of unmodified RBAC. The pores and cracks on the surface of RBA were significantly reduced and the interface transition zone (ITZ) of RBA was compacted after silane modification of RBA. RBA contained Si, Fe, Al, Ca elements and a small amount of Na, K, Mg elements brought by mineral powder; the content of Ca, O, Si elements in ITZ and cement mortar were rich, which indicated that there were a large amount of calcium silicate hydrate (C-S-H) in ITZ and cement mortar; ITZ and cement mortar contained Al elements, which indicated that there were ettringite and monosulfate; the content of Ca element in RBA and ITZ increased after silane modification of RBA, which indicated that silane hydrolyzed and reacted with free calcium ions to form calcium silicate.

中文翻译：

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硅烷改性再生砖骨料混凝土的显微组织分析

再生砖骨料（RBA）和再生混凝土骨料（RCA）之间存在本质区别。RCA的薄弱区是附着在骨料表面的旧砂浆，而RBA的薄弱区是其自身较大的孔隙率。硅烷具有小分子结构，能以水为介质渗透到混凝土中，与混凝土中的活性官能团发生反应，形成硅烷聚合物的网状结构。本文采用 8% 硅烷溶液对再生砖骨料混凝土 (RBAC) 进行了两种改性。第一种方案是将RBA浸泡在8%的硅烷溶液中，第二种方案是在RBAC的混合过程中加入8%的硅烷溶液而不是水。结果表明，与未改性的RBA相比，RBA硅烷改性后的表观密度增加了5倍。48%，吸水率下降61.12%，破碎指数下降11.09%。RBAC与硅烷改性RBA的平均抗压强度比未改性RBAC高11.72%，RBAC与硅烷混合的平均抗压强度比未改性RBAC低9.12%。RBA硅烷改性后，RBA表面的气孔和裂纹明显减少，RBA界面过渡区（ITZ）被压实。RBA含有Si、Fe、Al、Ca元素和少量矿粉带来的Na、K、Mg元素；ITZ和水泥砂浆中Ca、O、Si元素含量丰富，表明ITZ和水泥砂浆中含有大量的水合硅酸钙（CSH）；ITZ和水泥砂浆中含有Al元素，表明有钙矾石和一硫酸盐；