Storage stability of cuplump modified bitumen binder

Polymer-modified bitumen (PMB) has been increasingly used to enhance pavement performance. Many polymers have been used for bitumen modification, including polyethylene, polyolefins, and elastomers such as Natural Rubber (NR) and Synthetic Rubber (SR). Commercially, the natural rubber modified bitumen which produced from cuplump is prepared at high temperature and occasionally stored for a certain period at elevated temperature which could create stability problems and separation; in fact, polymers and bitumen components can lose most of the benefits from the modification due to separation during the storage phase. Hence in this work, effect of hot storage on the Cuplump Modified Bitumen (CMB) properties containing 6% of rubber weight were investigated. The CMB was heated and continuously stirred at 120 degrees C and 160 degrees C for periods up to 7 days. Changes in physical properties such as viscosities, penetration, softening, rheological and chemical properties were monitored by thermogravimetry (TGA) and Fourier-transform infrared (FTIR) analysis. Results showed that the penetration, softening point and viscosity were less affected by both storage conditions. A negligible effect was also found in the thermogravimetric analysis (TGA), where the combustion temperatures sustain at values 469 degrees C, while similar peaks of CMB were observed by FTIR determination. Indeed, the absence of sulfoxide and carbonyl peak indication of no oxidation occurred. Results indicated that the CMB was stable at both temperatures of 120 degrees C and 160 degrees C with continuous and homogenous agitation throughout storage duration without experiencing significant degradation. The continuous agitation during storage managed to avoid rubber separation from occurring and maintaining the rubber in colloidal suspension in bitumen matrix preventing from flocculating.