Table2_Multi-Technique Approach to Enhance the Properties of Fine Recycled Aggregate Concrete.XLSX

This study investigated the properties of fine recycled aggregates (FRA), with a view to enhancing their properties for structural concrete applications. The study explored several approaches including mixing; curing; systematic screening of FRA particles below 1.18 mm to reduce the adhered cement paste (ACP) content; and the use of fly ash as 30% cement replacement to modify the microstructure of FRA concrete. To test these approaches, two series of concrete mixes were prepared at 0.45 and 0.55 w/b ratio, with FRA replacing natural sand at 0, 25, and 50% by mass, and tests were carried out after 3, 28, and 180 days of curing. Results show that the combination of ACP reduction and fly ash treatment significantly enhanced the compressive strength and elastic modulus of FRA concrete, especially at 180 days, through microstructure modification and pozzolanic reactions.

本研究围绕细再生骨料（fine recycled aggregates, FRA）的性能展开探究，旨在优化其性能以适配结构混凝土应用。研究探索了多种改性路径，包括拌合工艺调控、养护制度优化、对粒径小于1.18mm的FRA颗粒进行系统筛分以降低附着水泥浆（adhered cement paste, ACP）含量，以及采用粉煤灰（fly ash）替代30%的水泥以调控FRA混凝土的微观结构。为验证上述方案的有效性，研究制备了两组混凝土配合比，水胶比（water-to-binder ratio, w/b）分别为0.45和0.55，以FRA按质量占比0%、25%、50%取代天然砂（natural sand），并分别在养护3天、28天、180天后开展性能测试。试验结果表明，通过微观结构调控与火山灰反应，降低附着水泥浆含量结合粉煤灰改性的复合方案，可显著提升FRA混凝土的抗压强度与弹性模量，尤其在养护180天时的改性效果更为突出。