Iowa Statewide Urban Design and Specifications

About the research

This project will evaluate the performance of a mineral-blended polymeric microsphere powder used to construct concrete pavement test sections at MnRoad. The microsphere concrete mixtures will also be compared with a reference mixture that contains conventional air entrainment and existing mixtures evaluated at MnRoad. Performance will be monitored over a three-year period. The three-fold objectives for evaluating the microsphere mixtures are as follows:

1. Determine the reductions in cement content that can be achieved with typical pavement concrete mixtures in which air-entraining agents are replaced with the microsphere-powder blend.
2. Develop test data on strength and freeze-thaw durability for selected concrete mixtures to support application of the microsphere concrete mixtures in pavement construction.
3. Quantify the sustainability benefits of use of microsphere concrete in lieu of conventional air- entrained concrete mixtures

Laboratory testing on specimens cast during pavement construction will be performed to evaluate strength, modulus of elasticity, resistivity, and freeze-thaw durability. Field data collection will include surface distress surveys, falling weight deflectometer (FWD) testing, ride quality measurements, joint faulting and movement, embedded strain sensor data, ultrasonic tomography (MIRA) testing, curling and warping measurements, and examination of core samples. Results from this project will demonstrate the effectiveness of the mineral-blended polymeric microsphere powder to be used in concrete mixtures to support reductions in cementitious materials content while also supporting freeze-thaw durability. The feasibility of using mineral-blended polymeric microsphere powder in large-scale pavement applications will be evaluated, as well as the impact of use of this material to support both durability performance and reduced environmental impact of concrete. Findings of this work may also support use of mineral-blended polymeric microsphere powder in applications where supplementary cementitious material (SCM) characteristics may cause issues with conventional air-entraining admixtures (e.g., higher carbon fly ash), thus allowing marginal SCMs to be more readily used in concrete.