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

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。

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

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.