纤维纳米混凝土力学性能和抗氯离子渗透性能的研究

通过坍落度、贯入阻力试验,不同龄期抗压强度、劈拉强度和抗折强度试验以及氯盐溶液浸泡干湿循环试验,探讨了钢纤维掺量、纳米矿粉种类和掺量以及混凝土基体强度对纤维纳米混凝土工作性能、凝结时间、基本力学性能和抗氯离子渗透性能的影响.结果表明:随钢纤维掺量增加,纤维纳米混凝土坍落度逐渐减小,各龄期强度和28 d龄期抗氯离子渗透性能呈增大趋势;随纳米SiO2掺量增加,拌合物坍落度快速降低,初凝、终凝时间缩短,各龄期强度整体呈上升趋势且抗氯离子渗透性能逐渐提高;随纳米CaCO3掺量增加,坍落度先增加后减小,初凝时间逐渐缩短,终凝时间变化不显著,各龄期强度呈增大趋势且抗氯离子渗透性能逐渐提高;随混凝土基体强度降低,坍落度快速增大,初凝和终凝时间迅速延长,各龄期强度和28 d龄期抗氯离子渗透性能逐渐降低.钢纤维的掺入,改善了混凝土的破坏形式;纳米矿粉的掺入,改善了混凝土的微观结构,增加了混凝土基体的密实度.混凝土中掺入适量的纤维和纳米矿粉,有效改善了混凝土的性能.

Research on Mechanical Properties and Chloride Ion Penetration Resistance of Fiber and Nanometer Materials Reinforced Concrete

Through the slump and penetration resistance tests,compressive and splitting and flexural strength tests at different ages,and chloride ion permeating resistance experiment on the specimens,the effects of steel fiber content,nanometer material type and content,and matrix strength of concrete on working performance,setting time,mechanical properties and chloride ion penetration resistance of fiber and nanometer materials reinforced concrete(FNMRC) were studied.The results showed that the slump of FNMRC mixture decreased and compressive,splitting and flexural strength and chloride ion penetration resistance of FNMRC increased with the increasing steel fiber content;with the increasing replacement rate of cement by nanometer SiO2,the slump decreased quickly,initial and final setting time shortened,mechanical properties and chloride ion penetration resistance increased;with the increasing replacement rate of cement by nanometer CaCO3,slump first increased and then decreased,and initial setting time shortened,mechanical properties and chloride ion penetration resistance increased;with the decreasing strength grade of concrete,slump increased and initial and final setting time prolonged quickly,mechanical properties and chloride ion penetration resistance decreased gradually.The microstructure,destruction form,compactness,working performance,mechanical properties and chloride ion penetration resistance of FNMRC were all improved by adding in right quantity of steel fiber and nanometer materials.