废瓷砖再生砂掺配率对砂浆强度的影响及机理分析

固定水泥的用量比例与稠度制作砂浆试件,对五种废瓷砖砂掺配率、四个养护龄期下的砂浆进行抗压强度和抗折强度试验,并采用扫描电子显微镜(SEM)观察细骨料以及骨料-水泥石界面的微观形貌,分析砂浆强度增长机理。试验结果表明,在同等试验条件下,随着废瓷砖砂掺配比率的增加,砂浆抗压强度增加,掺加废瓷砖再生砂可提高砂浆强度等级1~2个级别。五种砂浆的抗压强度与抗折强度均随养护龄期的增加呈现线性增长规律。SEM图像显示废瓷砖再生砂碎裂面为粗糙的层状多孔结构,与天然砂掺配使用增大了混合砂的骨料机械咬合力以及细骨料-水泥石的界面粘结力,从而提高了废瓷砖再生砂浆的整体强度。建议优先选用质地坚硬、干净无杂质的废弃贴面瓷砖作为原材料,采用两次以上破碎方式加工废瓷砖再生砂,以保证废瓷砖再生砂砂浆的强度。

Study on Influence to Strength of Masonry Mortar and Mechanism Analysis on Mixing Ratio of Sand Recycled by Wasted Ceramic Tiles

Wasted ceramic tiles have been broken into sandy gravel to configure reclaimed sand instead of normal sand.Bending strength tests and compressive strength tests of mortar samples have been carried out under different substitution rate of ceramic tile wastes sand in different curing time.The micro-structure of fine aggregate and aggregate-cement interface has been observed by scanning electron microscope(SEM),which has been used to analyze mortar strength growth mechanism.The results have indicated that strength grade of masonry mortar recycled by ceramic tile waste under different substitution rates could be improved 1 or 2 grades,and the strength linearly increases as the curing time increases under the same substitution rate.SEM images have shown that the crushing surface of recycled ceramic tile is a rough layered porous structure.Mixing with natural sand increases the mechanical bite force of mixed sand and the inter-facial bonding force of fine aggregate and cement,thus improves the overall strength of recycled ceramic tile mortar.It has been recommended to give priority to the hard,clean and non-impurities of the wasted tile as raw materials,and produce wasted tile recycled sand with the use of two or more crushing process to ensure the strength of recycled wasted tiles and mortar.