INVESTIGATION OF THE CURING VARIABLES OF ASPHALT-RUBBER BINDER

A curing study was undertaken to determine the effect of asphalt type, rubber content, rubber mesh size, rubber source, curing time, curing temperature, and rate of mixing on the properties of asphalt-rubber bi nder. Properties studied were asphalt composition, rubber dissolution, molecular weight distribution, and the low-, intermediate-, and high- temperature rheological properties. These properties were found to be dependent on the above listed variables. Most notable were the curing variables of curing time, curing temperature, and rate of mixing. Incr easing the curing time, curing temperature, and rate of mixing increas ed the amount of rubber dissolution into the asphalt during the curing process. Increased rubber dissolution was determined to improve the l ow- and intermediate-temperature rheological properties of a binder. F urthermore, after the initial increase in high-temperature viscosity w ith the addition of rubber, the high-temperature viscosity decreased s ignificantly with increased rubber dissolution.