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

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.

Waste Tyre Rubber Application in Semi-Rigid and Flexible Pavement

Increasing traffic requires durable and low-noise road surfaces. Urban residents complain about excessive traffic noise that leads to an unhealthy environment. Understanding techniques to produce durable, low-noise pavement has led to the development of rubberized concrete block pavement (RCBP) and rubberized asphalt concrete pavement (RACP). The chapter examines morphology and chemical properties of waste tyre rubber using FESEM, XRF, and TGA/DTA. Authors discuss characteristics of RCPB and RACP and conclude application of RCBP and RACP can lower traffic noise.

Design of Rubberized Asphalt Concrete by Means of Coarse Aggregate Void Filling Method

In order to find a convenient approach to design the mix of rubberized asphalt concrete (RAC) and make full use of the properties of RAC, a kind of RAC-13 (13 is the nominal maximum aggregate size of the mixture) was designed by means of coarse aggregate void filling method (CAVF). A series of conventional tests of asphalt mixture with five asphalt-rubber aggregate ratio(ARAR) were carried out to check the target mix design and evaluate the performance of RAC. Performance evaluation tests such as Marshall and submerged Marshall stability test, moisture damage test and wheel tracking test were included. Test results show that the high temperature stability, moisture susceptibility and road performance of RAC-13 designed with CAVF method are all favorable. The recommended optimum asphalt-rubber aggregate ratio(OARAR) is 7.1% under the condition of skeleton structure. CAVF is a good means for designing RAC to ensure its stone-on-stone contact structure.