Abstract

Tire-bead steel wires derived from the pyrolysis of waste-tires can be converted into the discrete reinforcement for fiber-reinforced concrete (FRC). This study for the first time presents the information about selecting the optimum dosage of recycled steel-fibers (RSF) in FRC application. Therefore, two most common types of RSF i.e., plain RSF (PRSF) and twisted RSF (TRSF) were incorporated in a high strength plain concrete (PC) at seven different volume fractions i.e., 0%, 0.25%, 0.5%, 0.75%, 1%, 1.5% and 2%. Both physical and mechanical properties of FRCs were studied including density, compressive strength-f_CU, modulus of rupture-f_R, splitting-tensile strength-f_SP, ultra-sonic pulse velocity-UPV, and water absorption-WA. The results revealed that TRSF performed better than PRSF in overall mechanical performance. Maximum compressive strength-f_CU, 9-12% higher than PC, was achieved with a 0.75% volume fraction of PRSF or TRSF. TRSF was extremely useful in upgrading the f_SP and f_R by more than 82% and 109%, respectively, at a 1.5% volume fraction w.r.t PC. PRSF-FRC showed lower permeability than TRSF-FRC at the same volume fraction. Lower volume fractions i.e., 0.25-0.5% RSF reduced the permeability of FRC, while higher volume fractions were detrimental to WA and RCP resistance. Experimental values of mechanical (i.e., f_SP and f_R) and permeability properties (i.e., WA and RCP) were accurately related to predicting RSF-FRC as a function of strength class of PC and reinforcement index.

摘要

从废轮胎热解中提取的胎圈钢丝可以转化为纤维增强混凝土 (FRC) 的离散增强材料。本研究首次提供了在 FRC 应用中选择再生钢纤维 (RSF) 最佳用量的信息。因此，两种最常见类型的 RSF，即普通 RSF (PRSF) 和扭曲 RSF (TRSF)，以七种不同的体积分数，即 0%、0.25%、0.5%、0.75% 掺入高强度素​​混凝土 (PC) 中, 1%, 1.5% 和 2%。研究了 FRC 的物理和机械性能，包括密度、抗压强度- f _CU、断裂模量- f _R、劈裂抗拉强度- f _SP、超声脉冲速度 - UPV、和吸水率-WA。结果表明，TRSF 在整体机械性能方面优于 PRSF。PRSF 或 TRSF 体积分数为 0.75% 时，可实现最大抗压强度f _{CU ，比 PC 高 9-12%。}TRSF 在将f _SP和 f _R分别提升 82% 和 109% 方面非常有用，相对于 PC 的体积分数为 1.5%。在相同的体积分数下，PRSF-FRC 的渗透率低于 TRSF-FRC。较低的体积分数，即 0.25-0.5% RSF 降低了 FRC 的渗透性，而较高的体积分数不利于 WA 和 RCP 阻力。机械实验值（即f _SP和f _R) 和渗透特性（即WA和RCP）与预测 RSF-FRC 准确相关，作为 PC 强度等级和加固指数的函数。