This research investigates the impact of mix design methods on the mechanical characteristics of steel fibre-reinforced concrete (SFRC) made with recycled aggregates (RA) obtained from a precast waste concrete. The experimental campaign was carried out in two phases. In phase I, three types of steel fibre (SF) differing only in shape were examined. Then, eight mixes were formulated, considering a range of SF volume ratios from 0.125% to 1.5%, using both normal and the Equivalent mortar volume (EMV) mix design methods. In phase II, a reference mix and two recycled aggregate concrete mixes were developed, one designed with normal method and the other with the EMV technique and incorporating their associated optimum SF content obtained in phase I. The results show that the mechanical properties of SFRC proportioned with the EMV approach is not adversely affected and that water absorption capacity of the concrete is improved with this method compared to the traditional method. Also, mix design method adopted for recycled concrete affects the optimum SF volume ratio.

这项研究调查了混合设计方法对用预制废混凝土获得的再生骨料（RA）制成的钢纤维增强混凝土（SFRC）的力学性能的影响。实验活动分为两个阶段。在第一阶段中，研究了三种仅形状不同的钢纤维（SF）。然后，使用普通砂浆和当量砂浆体积（EMV）混合料设计方法，考虑到SF体积比从0.125％到1.5％的范围，配制了8种混合料。在第二阶段，开发了一种参考混合料和两种再生骨料混凝土混合料，一种采用常规方法设计，另一种采用EMV技术并结合了在第一阶段获得的相关最佳SF含量。结果表明，与传统的方法相比，与EMV方法成比例的SFRC的机械性能没有受到不利影响，并且该方法提高了混凝土的吸水能力。同样，用于再生混凝土的配合料设计方法也会影响最佳的SF体积比。