Behavior of a draining mixture composed by recycled concrete aggregates and rubberized asphalt concrete

Abstract

Concrete waste is considered an environmental liability with a negative impact. However, this type of waste presents a high potential to be used as an alternative building material. Therefore, the present study aims to evaluate the applicability of substituting the conventional natural stone aggregate (CA) of a draining asphalt mixture (MD) by a recycled concrete aggregate (RCA). Firstly, RCA was physically characterized to be compared with the AC. Then, two MD mixtures were design with rubberized asphalt concrete (GCR by its spanish acronym): one using the conventional aggregate (control sample) and one with the RCA substituting entirely the CA. Experimental tests under monotonic load (indirect tensile strength - RTI) were conducted over the mixtures, as well as adhesion tests (susceptibility of RTI in wet and dry conditions and abrasion wear Cantabro). The results indicate that for MD mixtures with RCA, a higher content of asphalt is required than with CA. Additionally, it wasfound that the presence of higher asphalt content in MD-RCA mixtures increases its adhesion when compared with the control sample. Therefore, it can be concluded that the use the RCA for MD mixtures, in the proposed way, is technically and environmentally viable.

Evaluación de una mezcla asfáltica utilizando agregados reciclados de concreto. Caso de estudio. Clima de alta temperatura

“…However, there are some existing aspects that could discourage its use. For example, RCAs are highly heterogenous and present lesser mechanical resistances and hardness in comparison to NAs [10] [11][12]. This is mainly because of the fragility of the mortar adhered to RCA surface [13] [14] [15] and the presence of other impurites that are difficult to separate from C&D, such as brick, ceramic and clay roof tiles, among others [16].…”

“…Additionally, HMAs using RCAs in many cases comply with national Marshall design specifications for low and medium traffic [31][32][33] [22]. On the other hand, due to the high heterogeneousness of RCAs, studies conducted on HMA mixes present results that are contradictory [34] In order to improve some of the undesirable properties of HMAs that use RCAs, some researchers advise to pretreat RCAs (e.g., bitumen emulsion, Portland cement paste, slag cement paste, liquid silicone resin, abrasive mechanical pre-treatment, among others) before the production of the bituminous mix (e.g., [25][26] [35][15][36] [10]).…”