Viability of the Use of Nanoclay-Modified Asphalt Binders in Roofing Shingles

摘要

Asphalt shingles are the most commonly used material on residential roofs in the United States. Asphalt is the primary input in the production of roofing asphalt shingles. In the production process of modified asphalt membranes for shingles, asphalt is modified with thermoplastic polymers such as atactic-polypropylene (APP) and styrene-butadiene-styrene (SBS). On the other hand, the use of nanoclays or organoclays is a potential alternative of traditional polymers, which are very expensive and not abundant. Nanoclays are derived from naturally occurring clay minerals and are capable of improving the physical and mechanistic properties of polymers and rubbers. Studies have showed that nanoclays improve stiffness, aging, and fire resistance behavior of asphalt binders. The objective of this study is to find out the viability of nanoclay as a modifier for asphalt binders to be used in roofing shingles and to find out the moisture susceptibility of nanoclay-modified asphalt binders by surface free energy analysis. To this end, different percentages of natural nanoclays in the form of bag fines (PBF) obtained from a local asphalt plant were used modify a base (straight run) binder. Nanoclays have not shown any detrimental effects on the delamination resistance of the binder. Thus, nanoclays are expected to be a viable alternative of expensive polymers and have potentials to reduce material costs, produce durable shingles, and induce sustainability in asphalt roofing practices in the United States.