Environmental effect on the time available for compaction of warm mix asphalt / Nurul Syahirah Fatinah Mustapa

High demand for new asphalt pavements often requires that paving is to be done in an
unfavourable condition such as low air temperatures, high wind speeds, and night
construction that will influence the cooling rate of asphalt pavements, affecting the
Time Available for Compaction (TAC). TAC is the period taken by the asphalt mix to
cool and stiff to the point where it can absorb the applied compaction energy without
allowing the aggregate particles to move. This study was conducted with the aim to
determine the appropriate TAC of Warm Mix Asphalt (WMA) which include the
study parameters of wind speed, solar flux, base and ambient temperature, and rain
intensity. Marshall mix design method was used for AC14 and AC28 mix type based
on PWD Malaysia‟s specifications for Road Works. The liquid additive used to
modify the binder to make the WMA samples was Cecabase. The volumetric
properties were first determined together with the optimum cecabase content (OCC)
of WMA. Then, the cooling rate of WMA was measured by investigating the
environmental effects of wind speed, solar flux, base and ambient temperature, and
also rain intensity. Temperature measurements were taken in the middle and the
surface position of the slab samples. Relationship between environmental factors and
TAC were developed. Based on the results obtained, the TAC of WMA decreased by
12-100% during windy, night and rainy condition compared to control samples, while
TAC increased of up to 63% during daytime condition. It can be concluded that the
cooling rate of WMA is significantly affected by the environmental factors and TAC.