SBIR Phase I: Low-cost Piezoelectric Sensor for Quality Assurance of Asphalt Binders used in Highway Construction

This Small Business Innovation Research (SBIR) Phase I project addresses the paving industry's need to monitor changes in asphalt binder properties in real time. It aims to develop an advanced prototype of a piezoelectric-based testing system to rapidly verify the uniformity and specification compliance of asphalt binders for quality control (QC) and verification testing purposes. Supply of asphalt concrete (AC) for paving is a $25-32 billion industry in the United States; of this, the cost of asphalt binders is around $6-8 billion. Assuring binder uniformity and specification compliance is therefore of great importance to suppliers, contractors and owner agencies. The successful realization of the proposed device will help minimize project delays and premature failures, as well as the associated litigation. Assuming 5 percent of the AC placed results in early failures related to binder quality, the device has the potential to save at least $1 billion annually. The ability to measure the binder's rheological attributes in-situ, between binder production and mixing of the asphalt, is currently unavailable in the market. Such data will enhance the industry's understanding of the impacts of binder production, storage and transport process on its uniformity. This will help improve the production processes within the industry and achieve longer-life roadways. The intellectual merit of this project lies in its emphasis on real time binder uniformity measurement in terms that are directly relatable to the properties measured by the standard specification used to accept asphalt binders in the US: AASHTO M320. Moreover, the device will be designed to be field-portable and cost-effective to promote widespread adoption. The impetus for such a device has never been greater given the sharp rise in post-refinery modifications of asphalt binders at blend terminals or at the contractor's plants. This effort will leverage the bench-top prototype system developed under previous national research studies, and which has been deemed feasible, in concept, to deliver the key parameters needed to do QC of asphalt binders. This project will specifically address several technical challenges including miniaturization of base unit electronics into a hand-held unit suitable for field testing, optimizing the piezoelectric sensor materials and dimensions for broadest operating range, design of a base unit for field operation, establishing QC test methodology, developing numerical techniques for data reduction, and integrating hardware and software. The anticipated results from this effort will be (i) a functional prototype and (ii) the realization of methodology and software for quality control testing.