Optimization of mix proportion of alkali-activated slag mortars prepared with seawater and coral sand
Optimization of mix proportion of alkali-activated slag mortars prepared with seawater and coral sand
复制标题
DOI：
10.1016/j.conbuildmat.2021.122805
复制
发表时间：
2021-05
影响因子：
7.4
通讯作者：
Bai Zhang;Hong Zhu;K. W. Shah;Pan Feng;Zhiqiang Dong
中科院分区：
文献类型：
--
作者：
Bai Zhang;Hong Zhu;K. W. Shah;Pan Feng;Zhiqiang Dong
为了有效利用海洋资源，促进建筑业的可持续发展，提出了一种新型建筑材料--海水珊瑚砂碱矿渣砂浆(SC-AAM)，并对其工作性、凝结时间、抗压强度、抗折强度和干缩性能进行了研究。采用田口正交试验设计方法，考察了水玻璃的模数(Ms)、Na2O与粘结剂的重量比(N/B)、珊瑚砂对海砂的置换率(Rs)、水胶比(W/B)等因素对固化效果的影响。实验结果表明，随着碱激发剂模数和碱含量的增加，胶凝材料的抗压和抗折强度提高，凝结时间缩短，干燥收缩增大。根据上述正交试验结果，确定了SC-AAM的最佳配比为：ANMS=11.2，AN/B=10.4%，Aw/B=0.45，ARS=0.100%。然后，采用扫描电子显微镜(SEM)和X射线衍射仪(X射线衍射仪)对以此最佳配合比制备的SC-AAM的微观结构和晶相进行了分析，并以掺入海水和珊瑚砂的水泥砂浆为参照。结果表明，碱激发材料的使用改变了砂浆的反应水化产物，改善了珊瑚砂与泥浆的界面微观结构。此外，珊瑚砂的存在降低了AAM的干燥收缩，这是由于珊瑚集合体内部的自养效应造成的。
To effectively utilize marine resources and promote sustainable development in the construction industry, an innovative building material, namely, alkali-activated slag mortars prepared with seawater and coral sand (SC-AAMs), was proposed in this paper, and its workability, setting time, compressive strength, flexural strength, and drying shrinkage were studied. The effects of the modulus of sodium silicate (Ms), Na2O-to-binder (N/B) ratio by weight, replacement ratio of the coral sand for sea sand (Rs), and water-to-binder (W/B) ratio were considered using the Taguchi orthogonal experimental design method. The experimental results indicated that an increased alkali activator modulus and alkaline contents improved the compressive and flexural strengths, however, resulting in a decreased setting time and an increased drying shrinkage. According to the results from the aforementioned orthogonal experiments, the optimum mixtures for SC-AAMs were determined to be anMs= 1.2, aN/B= 4%, aW/B= 0.45, and aRs= 100%. Then, the microstructure and crystalline phases in the SC-AAMs prepared with this optimum mix proportion were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively, and the cement mortar mixed by seawater and coral sand was selected as the reference. It can be concluded that the utilization of the alkali-activated materials changed the reaction hydrate products of the mortars and improved the interfacial microstructures between the coral sand and slurry. In addition, the existence of the coral sand reduced the drying shrinkage of the AAMs due to the self-curing effect inside the coral aggregate.