Xu Wenyu, Wang Hui, Tian Xiaoning
Nanjing University of Science and Technology ZiJin College, Nanjing 210023, China.
School of Civil Engineering and Geographic Environment, Ningbo University, Ningbo 315000, China.
Materials (Basel). 2023 Jul 27;16(15):5265. doi: 10.3390/ma16155265.
Secondary aluminum ash is a kind of common solid waste which will pollute the environment without any treatment. In this study, the influence of secondary aluminum ash on the rheological properties and the initial setting time of fresh reactive powder concrete (RPC) are researched. Meanwhile, the mechanical properties and the drying shrinkage rates of RPC with the secondary aluminum ash are determined. The electrical parameters of RPC with the secondary aluminum ash are measured. Scanning electron microscopy is obtained to reflect the internal structure of RPC. Results show that the addition of secondary aluminum ash can lead to decreasing the fluidity and increase the yield shear stress of fresh RPC paste by varying rates of 16.1% and 58.3%, respectively. The addition of secondary aluminum ash can decrease the flexural and compressive strengths of RPC cured for 1 day by the decreasing rates of 018.7% and 019.3%. When the curing age is 28 days, the flexural and compressive strengths of RPC are increased by 09.1% and 019.1% with adding the secondary aluminum ash. The secondary aluminum ash can promote the condensation of RPC. The addition of the secondary aluminum ash can decrease the electrical resistance of RPC by an order of magnitude. The relationship between the electrical resistance and the electrical reactance fits the quadratic function equation. The electrical resistance of the pore solution increases in the form of a quadratic function with the mass ratio of the secondary aluminum ash. The dry shrinkage rates of RPC cured for 1 day and 28 days are decreased by 036.4% and 041.3% with the increasing dosages of secondary aluminum ash. As obtained from the microscopic testing results, the secondary aluminum ash can improve the compactness of hydration products.
二次铝灰是一种常见的固体废弃物，未经处理会污染环境。本研究探讨了二次铝灰对新型活性粉末混凝土（RPC）流变性能和初凝时间的影响。同时，测定了掺二次铝灰RPC的力学性能和干燥收缩率。测量了掺二次铝灰RPC的电学参数。通过扫描电子显微镜观察来反映RPC的内部结构。结果表明，添加二次铝灰会导致新拌RPC浆体的流动性分别以16.1%和58.3%的不同速率降低，屈服剪应力增加。添加二次铝灰会使养护1天的RPC的抗折强度和抗压强度分别以018.7%和019.3%的降低率下降。当养护龄期为28天时，添加二次铝灰使RPC的抗折强度和抗压强度分别提高09.1%和019.1%。二次铝灰可促进RPC的凝结。添加二次铝灰会使RPC的电阻降低一个数量级。电阻与电抗之间的关系符合二次函数方程。孔溶液的电阻随二次铝灰质量比呈二次函数形式增加。随着二次铝灰掺量增加，养护1天和28天的RPC干燥收缩率分别降低036.4%和041.3%。从微观测试结果可知，二次铝灰可提高水化产物的密实度。
