ABSTRACT

During the past few decades, the engineering and geotechnical properties of recycled concrete aggregate (RCA) has been investigated to evaluate its potential to use as a road construction material. This research studied the usage of polyvinyl alcohol (PVA) and cement for improving the mechanical strengths of RCA to be used as an alternative material in pavement base/subbase applications. The results showed that mixing PVA > 1.5% into the cement-stabilised RCA has a vital role in improving the compressive strength along with gaining a higher modulus of toughness. The unconfined compressive strength (UCS) value of stabilised RCA with 3% cement and RCA with 3% cement and 1.5% or 2% PVA met the minimum requirement for 7 days of curing. The addition of PVA reduced the resilient modulus (M_R); however, the M_R value of all blends was still higher than the minimum recommended value. The specimens with 28 days of curing had higher resilient modulus values than 7-day cured samples. The CBR value and swelling in soaked condition reduced with increasing the PVA content. The cement-PVA-stabilised RCA, as a supplementary material with up to 1.5% or 2% PVA content and 3% General Portland (GP) were found to have physical and strength properties, which comply with road authority requirements.

摘要

在过去的几十年里，人们对再生混凝土骨料 (RCA) 的工程和岩土特性进行了研究，以评估其用作道路建设材料的潜力。本研究研究了使用聚乙烯醇 (PVA) 和水泥来提高 RCA 的机械强度，以用作路面基层/底基层应用中的替代材料。结果表明，将 > 1.5% 的 PVA 混合到水泥稳定的 RCA 中对于提高抗压强度以及获得更高的韧性模量具有至关重要的作用。含 3% 水泥的稳定 RCA 和含 3% 水泥和 1.5% 或 2% PVA 的 RCA 的无侧限抗压强度 (UCS) 值满足 7 天固化的最低要求。PVA的加入降低了弹性模量（M _R）；然而，M_{所有共混物的R}值仍高于最低推荐值。固化 28 天的样品比固化 7 天的样品具有更高的弹性模量值。随着 PVA 含量的增加，CBR 值和浸泡条件下的溶胀度降低。水泥-PVA 稳定的 RCA 作为一种补充材料，其中 PVA 含量高达 1.5% 或 2% 和 3% 通用波特兰 (GP)，被发现具有符合道路当局要求的物理和强度特性。