不同养护条件下GBFS高强水泥基材料的力学性能

Mechanical Properties of GBFS High Strength Cement Based Materials under Different Curing Conditions

摘要:

针对标准养护、70℃蒸汽养护、高温压蒸釜养护3种养护条件下的粒化高炉矿渣（GBFS）高强水泥基材料进行力学性能试验,研究了养护条件、水胶比和代砂率等对GBFS高强水泥基材料抗压强度、抗折强度、劈裂抗拉强度和弹性模量等力学性能的影响及其各力学性能之间的关系,并通过激光共聚焦显微镜分析了养护条件对GBFS高强水泥基材料微观结构的影响.结果表明：GBFS高强水泥基材料的强度发展规律与普通石英砂高强水泥基材料相一致,其抗压强度、抗折强度、劈裂抗拉强度及弹性模量均随水胶比的降低、养护龄期的增加及养护温度的增高而增大;相同配合比、相同养护条件下,GBFS高强水泥基材料的抗压强度等力学性能低于普通石英砂高强水泥基材料;70℃蒸汽养护和高温压蒸釜养护不仅能提高GBFS高强水泥基材料的早期强度,还使其后期强度的发展高于标准养护;3种养护条件下GBFS高强水泥基材料的抗折强度、抗劈裂拉强度及弹性模量均随着抗压强度的增加而增加,其中弹性模量与抗压强度的关系可用通常混凝土计算公式描述.微观形貌显示：在标准养护条件下,GBFS高强水泥基材料与普通石英砂高强水泥基材料一样,其骨料界面过渡区中的水泥浆体与骨料紧密结合,但可明显分辨;70℃蒸汽养护条件下,其骨料与胶凝浆体界面过渡区发育较致密;高温压蒸釜养护条件下,其骨料与胶凝材料融为一体,界面过渡区已无法分辨.

Abstract:

Through the mechanical performance test of granulated blast furnace slag(GBFS) high strength cement based materials under different curing conditions, the mechanical properties such as compressive strength, flexural strength, split tensile strength and elastic modulus of GBFS high strength cement based materials with 2 water binder ratio and 3 sand replacement rates under standard curing, 70℃ steam and high temperature autoclave curing conditions were tested and the relationship between them were studied. And the effect of microstructure on mechanical properties of the composites under different curing conditions was analyzed by laser focusing microscope. The results show that the strength development law of GBFS high strength cement based materials is the same as that of ordinary quartz sand high strength cement based materials. The compressive strength, flexural strength, split tensile strength and elastic modulus all decrease with the decrease of water binder ratio, increase of curing age and curing temperature. Under the same mix ratio and the same curing conditions, the mechanical properties such as the compressive strength of GBFS high strength cement based materials is lower than those of ordinary quartz sand high strength cement based materials. 70℃ steam curing and high temperature autoclave curing can not only improve the early strength of GBFS high strength cement based materials, but also make the late strength development higher than that for standard curing. Under three curing conditions, the flexural strength, splitting tensile strength and elastic modulus all increase with the increase of compressive strength, and the relationship between elastic modulus and compressive strength can be described by the usual concrete calculation formula. The microscopic morphology shows that under standard curing conditions, GBFS high strength cement based materials are the same as ordinary quartz sand high strength cement based materials, the cement paste in the transition zone of the aggregate interface is closely combined with the aggregate, but it can be clearly distinguished. Under 70℃ steam curing conditions, the transition zone between the aggregate and the cementitious slurry is densely developed. Under the high temperature autoclave curing condition, the aggregate and the cementitious material are integrated, and the interface transition zone can no longer be distinguished.