01336706

Component

http://dx.doi.org/10.3141/2208-12

The drying of aggregates is a critical step in obtaining moisture-free hot-mix asphalt (HMA). The drying depends on many factors, which include the absorption and the moisture content of the aggregates as well as the drying temperature and time. The effect of drying of the aggregates on the moisture content of the resultant HMA needs to be understood so that adequate drying can be carried out for mixes, such as warm-mix asphalt (WMA), which are produced at lower than conventional temperatures. The objectives of this study were (a) to develop a laboratory method to produce HMA samples with various moisture contents that mimic insufficient drying of aggregates in a drum mixer and (b) to develop a nondestructive laboratory testing procedure to determine moisture content of compacted HMA samples. Aggregates with relatively high and low absorption rates were selected. A practical method was developed to mimic the retention of aggregate moisture in HMA in the laboratory. Good correlation was obtained between drying time and moisture-content loss for the aggregates of high and low water absorption. An experiment with heat transfer and a simulation with a finite element method confirmed the presence of moisture and its significant effect on the thermal conductivity of the mixes, which provided a nondestructive approach to determine moisture content of compacted HMA samples.

01356747

11-3346

English

pp 90-96

2011

Transportation Research Record: Journal of the Transportation Research Board

9780309167390

Print

Figures (5) ; Photos (7) ; References (5) ; Tables (2)

Aggregates; Asphalt mixtures; Drying; Finite element method; Heat transfer; Hot mix paving mixtures; Laboratory tests; Moisture content; Nondestructive tests; Simulation; Thermal conductivity; Warm mix paving mixtures

Highways; Materials; Pavements; I31: Bituminous Binders and Materials; I36: Aggregates

TRIS, TRB, ATRI

Nov 30 2011 9:21AM

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