Stabilized mortar with air incorporator agent and plasticizer set retarder: performance measurement

Abstract This study aims to develop three stabilized mortars to masonry using air entraining agents and settling retardant plasticizer to compare with a conventional mortar with lime. It was analyzed consistency index, specific gravity, air entrained content, water retentivity, setting time through the heat of hydration, mortar shrinkage/expansion, compressive strength, resistance to sulphate and tensile strength in bonding. The results exhibited that the presence of the settling retardant plasticizer affected the consistency index making the mortar more workable for a longer time. The presence of additives made the stabilized mortars lighter with lower mass density and higher incorporated air content. The presence of lime provided high water retentivity in the conventional mortar while the setting retardant plasticizer improved the water retentivity in the stabilized mortars. The initial setting time of the stabilized mortars occurred after approximately 50 hours. Conventional mortar lost its workability quickly after 2 hours. In conventional mortar, shrinkage occurred, while stabilized mortars had expansion. The conventional mortar exhibited better compressive strength, while the excess of additives can affected negatively this property in the stabilized mortars. Conventional mortar proved to be less resistant to sulphate attack. Tensile strength in bonding was better in a stabilized commercial mortar tested.摘要 本研究旨在开发三种用于砌体工程的稳定型砂浆，采用引气剂（air entraining agents）与抗沉降塑化剂（settling retardant plasticizer）制备，并与传统石灰砂浆开展对比试验。本次试验对稠度指数（consistency index）、表观比重（specific gravity）、含气量（air entrained content）、保水性（water retentivity）、通过水化热（heat of hydration）测定的凝结时间（setting time）、砂浆收缩/膨胀性能、抗压强度（compressive strength）、抗硫酸盐侵蚀性能（resistance to sulphate attack）及粘结抗拉强度（tensile strength in bonding）展开了测试分析。研究结果表明，抗沉降塑化剂的引入可优化砂浆的稠度指数，使其在更长时间内维持良好的工作性；外加剂的添加可降低稳定型砂浆的表观密度，使其质量更轻，同时提升砂浆的含气量。传统石灰砂浆具备更高的保水性，而抗沉降塑化剂则可改善稳定型砂浆的保水性能。稳定型砂浆的初始凝结时间约为50小时，而传统砂浆在2小时后便快速丧失工作性。传统砂浆表现出收缩特性，稳定型砂浆则呈现膨胀特性。传统砂浆的抗压强度更优，但过量的外加剂会对稳定型砂浆的抗压性能产生负面影响。传统砂浆的抗硫酸盐侵蚀性能较差，经测试的商用稳定型砂浆具备更优异的粘结抗拉强度。