混杂纤维增强再生砖骨料混凝土增强机制与抗压性能计算方法

Reinforcing mechanism and calculation method of compressive behavior of hybrid fiber reinforced recycled brick aggregates concrete

通过钢-聚烯烃混杂纤维增强再生砖骨料混凝土(HF/RBAC)的抗压与弹性模量试验,研究了再生砖骨料(RBA)取代率、混杂纤维掺量、纤维种类对混凝土抗压强度和弹性模量的影响。根据RBA的XRD图谱、X-CT图像、RBA火山灰活性成分与水泥水化产物反应原理及能量平衡原理,分析了HF/RBAC的破坏机制和纤维增强机制。研究表明,当RBA全取代天然骨料(NA)时,HF/RBAC立方体抗压强度、轴心抗压强度和弹性模量分别降低了36.72%、24.95%和43.53%。当钢-聚烯烃混杂纤维体积掺量为1.5%时,HF/RBAC立方体抗压强度、轴心抗压强度和弹性模量分别增加了20.51%、30.33%和35.84%。最后,提出了考虑RBA压碎指标和取代率、纤维种类和掺量等因素影响的HF/RBAC抗压强度和弹性模量的计算方法。

The effects of replacement ratio of recycled brick aggregate(RBA),fiber volume content and fiber types on the compressive strength and elastic modulus of steel-polyolefin hybrid fiber reinforced recycled brick aggregates concrete(HF/RBAC)were investigated through compressive strength and modulus test.According to the XRD and X-CT image of RBA,the reaction theory of active components of RBA with cement hydration products and the energy balance,the failure mechanism and fiber reinforced mechanism of HF/RBAC were investigated.The results show that,when all of natural aggregate(NA)was replaced by RBA,the percentage decrements in the cubic compressive strength,prism compressive strength and elastic modulus of HF/RBAC are found to be 36.72%,24.95% and 43.53%,respectively.When the value of volume content of steel-polyolefin hybrid fiber is 1.5%,the percentage increments in the cubic compressive strength,prism compressive strength and elastic modulus of HF/RBAC are found to be 20.51%,30.33% and 35.84%,respectively.Finally,the calculation method of compressive strength and elastic modulus of HF/RBAC was proposed.It had taken into account some factors,such as the crushed values,replacement ratio of recycled brick aggregate,the fiber volume content and fiber type.