Optimum Fluid Content in Pavement Cold In-Place Recycling Containing Waste Materials

Abstract

The planning of road infrastructure undergoes major changes, especially in terms of sustainable development. Recycling of pavement structures involves the reuse of materials from existing pavement structures due to its timesaving and environmental benefits, as well as cost reduction. According to the recycling temperature, recycling can be hot and cold. This paper deals with cold in-place recycling and the determination of the optimum fluid content for by-product materials in mixtures compared with one containing natural zeolite. The content of bitumen emulsion and cement—which are the most used materials so far in cold recycling along with foam bitumen—was replaced with fly ash, slag or natural zeolite, and bakelite, respectively, while recycled asphalt pavement from Serbia (Žabalj) was used. Six different mixtures were made. The mixture with the addition of fly ash had the highest optimum fluid content (7.6%) compared with all test mixtures. Mixtures with slag, natural zeolite, and bakelite were in the range of a mixture containing 2% cement. Furthermore, the mixture with 3% cement had the lowest optimum fluid content (5.7%) in comparison to all the mixtures that were tested.

Fatigue of Cold Recycled Cement-Treated Pavement Layers: Experimental and Modeling Study

“…The stress corresponding to the ultimate load is the flexural tensile strength (FTS). The flexural tensile strain was computed using Equation (2). Flexural tensile strain at break (εb) corresponds to 95% of the ultimate flexural load.…”

“…1 All data were based on the SAPEM manual default values for each considered material. 2 There are no parameters for a 9000 MPa stiffness (used in MeDiNa analyses) in the SAPEM manual. 3 CRCTM ε b from Table 2, which were obtained using flexural tests.…”

“…There are two main kinds of pavement recycling: hot recycling, in which the materials need to be heated, and cold recycling, which consists of treating the existing pavement materials without heating processes. In cold recycling, asphalt additives, that is, emulsion [2] or foamed asphalt [3], and chemical additives are used alone or in combination to enhance the old pavement materials' behavior. Although it has several advantages [4], there is still a lack of application of cold recycling in comparison to other kinds of rehabilitation treatments (e.g., mill and fill).…”

“…Initially analyzed pavement structure. Used data were the default present in the MeDiNa software, which are based on laboratory tests on each material;2 For the CRCTMs, the moduli values and fatigue parameters presented in Figure2and Table2were used;3 MCT denotes Miniature Compacted Tropical, and NS' denotes Non-lateritic silty soil.…”

“…Inputs for the AASHTOWare PMED software. Advanced characterization data by;2 For the CRCTMs, data were those presented in Figure2and Table2. However, in PMED, minimum input values for FTS and E i are mandatory and were used (1.0 MPa and 1035 MPa, respectively); 3 Default data present in PMED for each material were used.…”