Investigation of Curing and Strength Characteristics of Cold-Mix Asphalt with Rice Husk Ash–Activated Fillers
Amal Raj, M. Sivakumar, M. V. L. R. Anjaneyulu
Abstract
Presently, the application of cold-mix asphalt (CMA) in structural layers of pavement is limited due to the slow curing rate and low early-life strength. This study attempts to achieve the reduction in curing period and improvement in strength development of CMA by using nonconventional fillers (NCFs) such as fly ash, ground granulated blast-furnace slag (GGBS), rice husk ash (RHA), and fly ash and GGBS activated with RHA. Curing rate was evaluated using moisture loss monitoring of mixture and compacted specimens of CMA. Strength development was evaluated using indirect tensile strength testing and wheel tracking testing. Laboratory investigations revealed that curing period and temperature have a significant impact on the rate of moisture loss and strength gain. Mechanical strength increased with the increase in curing period and temperature for cold mixes with NCFs. CMA with GGBS activated using RHA exhibited higher curing rates than conventional CMA and substantially higher early-strength development among all the mixes considered. This is due to the combined effect of moisture loss and accelerated hydration process. Statistical analysis also indicated that the improvement was significant. Thus, the use of GGBS with RHA as activator by partial replacement of mineral filler is a potential solution to prolonged curing period and weak early-life strength of CMA.