再生骨料对高钙粉煤灰基地聚物混凝土力学及耐久性能的影响

试验分别采用再生骨料和天然骨料作为粗骨料,制备了碱激发高钙粉煤灰基地聚物再生骨料混凝土和地聚物天然骨料混凝土。测试了其密度、抗压强度、劈裂抗拉强度、抗折强度、吸水率、渗透孔隙率、氯离子渗透深度及抗硫酸侵蚀等指标,探讨比较了再生骨料与天然骨料高钙粉煤灰基地聚物混凝土物理力学性能和耐久性的差异;并进一步分析了不同NaOH溶液浓度(6 mol·L~(-1)、12 mol·L~(-1)和18 mol·L~(-1))对其相关性能的影响。结果表明:再生骨料可以用作粗骨料制备高钙粉煤灰基地聚物混凝土,其抗压强度在30.64~38.22 MPa之间,略低于天然骨料制备的地聚物混凝土。随着NaOH溶液浓度的增加,粉煤灰基地聚物混凝土的力学性能及耐久性能均显著改善,且当NaOH浓度为12 mol·L~(-1)时,其各项性能综合较优。

Effects of Recycled Aggregate on Mechanical and Durability Properties of High Calcium Ash Geopolymer Concrete

Different mix proportions were designed according to the alkali-activated high calcium fly ash geopolymer concrete, which used recycled concrete aggregate(RCA) and natural crushed limestone(NLS) as coarse aggregate, respectively. The density, compressive strength, splitting tensile strength, flexural strength, water absorption, volume of permeable voids, chloride penetration depth and sulfuric acid resistance of recycled concrete aggregates fly ash based geopolymer concrete(GRC) were investigated and compared with fly ash geopolymer concretes containing natural crushed limestone(GNC). Furthermore, the effect of sodium hydroxide concentration on mechanical and durability properties of it was also researched. The results indicate that recycled concrete aggregate can be used as a coarse aggregate in fly ash geopolymer concretes with compressive strengths of 30.64MPa~38.22MPa which were slightly lower than those of fly ash geopolymer concretes containing crushed limestone. The mechanical and durability properties of fly ash geopolymer concretes were improved significantly with the increase of sodium hydroxide concentration. In addition, the use of sodium hydroxide concentrations of 12 mol.L-1 resulted in better comprehensive performances.