ABSTRACT

In this study, the usability and performance properties of recycled concrete aggregates (RCA) as granular road base (GRB) and granular road subbase (GRSB) material were investigated. A natural aggregate and the RCAs obtained from concretes with three different compressive strength and mixtures created by adding the RCAs to NA at the ratios of 25, 50 and 75% were used. Physical properties, modified Proctor, resilient modulus, permanent deformation, California bearing ratio (CBR), and permeability tests were carried out on all mixtures. Resilient modulus values (M_r) were obtained using three different resilient modulus models. The highest M_r value among pure RCAs was observed for RCA2 (average of 200 MPa). For the mixture samples, the highest M_r values were obtained in the mixtures containing RCA1 (average of 250 MPa). The minimum of permanent deformation value (ϵ_p) for the mixtures was obtained when the ratio of the RCA1 in the mixtures was 50% (ϵ_p = 0.238%). The obtained CBR values were not related to the M_r values, and the highest CBR values were found for the pure RCAs (average of 126%). High permeability coefficient values (average of 9.973×10⁻⁶ m/s) were obtained for the RCAs. As a result, it was more appropriate to blend the RCAs with the natural material rather than to use them in pure form. In general, it was appropriate to use 50% of RCAs in the mixtures. It was observed that if concrete compressive strength is as high as in RCA1 (18.5 MPa), RCA can be used even in the mixture at a ratio of 75%.

摘要

在这项研究中，研究了再生混凝土骨料 (RCA) 作为粒状路基 (GRB) 和粒状路基层 (GRSB) 材料的可用性和性能特性。使用从具有三种不同抗压强度的混凝土中获得的天然骨料和 RCA，以及通过将 RCA 以 25、50 和 75% 的比例添加到 NA 中产生的混合物。对所有混合物进行了物理性能、改性 Proctor、弹性模量、永久变形、加利福尼亚承载比 (CBR) 和渗透率测试。使用三种不同的弹性模量模型获得弹性模量值 (M _{r )。}在纯 RCA 中观察到 RCA2的最高 M _{r值（平均为 200 MPa）。}对于混合样本，最高的 M _r值是在含有 RCA1（平均 250 MPa）的混合物中获得的。当 RCA1 在混合物中的比例为 50% (ε _p = 0.238%)时，混合物的最小永久变形值 (ε _{p ) 得到。}获得的 CBR 值与 M _r值无关，纯 RCA 的 CBR 值最高（平均为 126%）。高渗透系数值（平均值为 9.973×10 ^-6m/s) 是针对 RCA 获得的。因此，将 RCA 与天然材料混合比以纯形式使用它们更合适。一般来说，在混合物中使用 50% 的 RCA 是合适的。据观察，如果混凝土抗压强度与 RCA1（18.5 MPa）一样高，则 RCA 甚至可以以 75% 的比例用于混合物中。