01154894

Component

This paper reports on research into the technical viability of recycling construction and demolition waste in hot mix asphalt. HMA mixtures were studied; containing different percentages of recycled aggregates (RA) from construction and demolition waste (C&D Waste). Control mixtures were also studied, similar in grading but not containing RA. Mixtures made with RA meet Spanish Marshall Parameters for roads with medium or low traffic volumes. Mixtures containing RA have considerable potential for stripping; a characteristic that can be related to the high water absorption of the mortar adhered to the RA. The moisture sensibility of HMA was evaluated by means of indirect tensile strength tests according to the European EN 12697-12 and EN 12697-23 standards. The results of the tensile strength ratios in mixtures with recycled aggregates were below the limits of 85% and 80% for binder courses and base courses, respectively. However, in HMA mixtures with conventional aggregates the results were higher than these thresholds. This stripping unfavorable result may be explained by the fact that, owing to the high water absorption of the mortar adhered to recycled concrete aggregates and ceramics, water can be retained inside the mixture, displacing the asphalt, producing an easy separation of the mortar and consequently resulting in a lower tensile strength ratio. It can be deduced that the use of RA from C&D waste in hot asphalt mixtures for road pavements is not yet feasible. Further research is needed to ensure the durability and technical viability of asphalt mixtures incorporating recycled aggregates. A few guidelines for this future research are given: reducing water absorption by lowering the percentage of RA; reducing water absorption by eliminating the mortar adhering to RA and also particles of ceramics; using improved fillers and adhesion agents; utilizing denser grading, with a lower percentage of voids, capable of making the mixtures less vulnerable to the effect of the water.

01147878

10-0021

English

2010

Transportation Research Board 89th Annual Meeting

DVD

Figures (1) ; Photos (6) ; References (20) ; Tables (6)

Aggregates; Bituminous materials; Calcites; Cement; Hot mix asphalt; Moisture content; Recycled materials; Schist; Stripping (Pavements); Tensile properties

Construction and demolition debris

Highways; Materials; Pavements; I31: Bituminous Binders and Materials; I32: Concrete

Transportation Research Board Annual Meeting 2010 Paper #10-0021

TRIS, TRB

Jan 25 2010 10:06AM