Treatments applied to recycled concrete aggregates when used in hot-mix asphalt

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- Investigación (ETSECCP) [819]
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Treatments applied to recycled concrete aggregates when used in hot-mix asphaltDate
2015Citation
Pasandín, A.R., Pérez., I., Gómez-Meijide; B. Treatments applied to recycled concrete aggregates when used in hot-mix asphalt. TRB 94th Annual Meeting, 2015.
Abstract
[Abstract:] The road construction industry is one of the major consumers of aggregate at the global level. The extraction of virgin aggregates entails several environmental, sociological and economic impacts. Therefore, reducing the consumption of natural aggregates is crucial to guarantee sustainable development. In this regard, in the last years, several research studies have been conducted dealing with the use of recycled concrete aggregates (RCAs) from construction and demolition wastes (C&DW) as aggregates for hot-mix asphalt (HMA). In general, from these investigations, it can be concluded that bituminous mixtures produced using partial replacement of natural aggregates with RCAs exhibit lower water resistance, which could adversely affect the durability of the HMA. To address this durability issue, in the present investigation, two simple and environmentally friendly treatments applied to the RCAs were analyzed and compared: 1)leave the mixture for 4 hours in the oven before compaction at the mixing temperature of 170 ºC and 2) pre-coat the RCA with 5% of bitumen emulsion prior to the mixing process. To evaluate the performance of HMA made with partial replacement of natural aggregate by RCA, the following measurements were conducted: the water resistance was determined by measuring the loss of indirect tensile strength, the stiffness was measured by means of the indirect tensile test (ITT) and resistance to the permanent deformation was determined by means of repeated load axial test (RLAT). Percentages of RCA of 5 %, 10%, 20% and 30% were used. Both treatments demonstrated their effectiveness in improving the water resistance of the mixtures. Moreover, the stiffness is higher in the mixtures with RCA and the rutting potential is satisfactory.
Keywords
Hot mix asphalt
Recycled concrete aggregates
Water resistance
Treatments
Recycled concrete aggregates
Water resistance
Treatments