不同循环模式下透水混凝土性能演变规律及损伤机制

Property Evolution Law and Damage Mechanism of Pervious Concrete under Different Cycle Modes

关键词:  透水混凝土  干湿-冻融循环  孔隙结构  演化方程  损伤机制

Key words:  pervious concrete  dry-wet and freeze-thaw cycle  pore structure  evolution equation  damage mechanism

摘要:

为探讨水对透水混凝土（PC）路面的影响，研究了干湿、冻融和干湿-冻融3种循环模式下PC性能的演化方程，揭示了单因素和双因素作用下PC的损伤机制.结果表明：添加玄武岩纤维（BF）虽然改变了PC的孔隙结构和初始性能，但并未影响损伤机制；冻融循环导致PC路面次生裂缝数量呈指数增长，与干湿循环作用下的性能演变规律不同；干湿循环在PC损伤前期引起孔隙壁表面物质溶解、流失和边缘卷曲剥离，冻融循环在PC损伤后期导致裂缝产生和扩展，造成颗粒间作用力断裂；在干湿-冻融循环耦合作用下PC性能指标降低程度超过干湿和冻融循环单因素作用结果之和.

Abstract:

In order to investigate the effect of water on pervious concrete （PC） pavement， the performance evolution equations of PC under three cycle modes of dry-wet， freeze-thaw， dry-wet and freeze-thaw were studied， and the damage mechanism under single and double factors were revealed. The results show that the basalt fiber（BF） changes the pore structure and initial property of PC， but does not affect the freeze-thaw damage mechanism. The secondary cracks of PC pavement caused by freeze-thaw cycle increase exponentially， which is different from the performance evolution law under dry-wet cycle. Dry-wet cycle in the early stage of damage causes the dissolution， loss of pore wall surface material and edge curl and peel， while freeze-thaw in the late stage of damage causes the formation and expansion of cracks， resulting in intergranular fracture. Under the coupling effect of wet-dry cycle and freeze-thaw cycle， the PC performance index decreases more than the single factor superposition of wet-dry cycle and freeze-thaw cycle.