Project Details
RESEARCHERS
Alex Hak-Chul Shin, Denita Walker
KEYWORDS
Bond strength (Materials), Concrete pavements, Curing agents, Lightweight aggregates, Paving materials, Recycled materials, Repairing
Project description
Being that pavement repair and construction represents a significant percentage of federal and state funding, new materials are being investigated to reduce cost and generate a more resilient material. The goal of the project is to develop cost-effective, high performance concrete materials for rapid pavement repair minimizing environmental impact. Experimental study was conducted to investigate sustainable concrete with recycled concrete aggregate (RCA), lightweight aggregate (LWA), and other materials to be used in rapid full-depth repair. To minimize cracking at early age, internal curing (IC) was adapted with RCA and LWA. RCA and LWA is a viable and practical way of producing rapid repair concrete with less drying shrinkage. 10% replacement of silica fume was found to improve performance as necessary as introducing pre-soaked aggregates increases moisture affecting hydration of concrete specimen and decrease drying shrinkage. Further investigation on the materials and techniques together by conducting test trials consisting of fully and partially adding wet and nonwet RCA and LWA, is studied to satisfy the sustainable aspect of the research as a viable method for today’s standards. The Vibration-free concrete (VFC) mixtures provided by Dr. Feys in Missouri University S&T were modified to study the applicability in rapid pavement repair. The modified mixtures were used to study the effects of four different curing conditions (ambient, heat blanket, heat fan, and oven) and the results are presented. The study shows that heating can expedite the strength gain in early age, and oven curing was the best among the curing conditions. The blanket with higher hearing capacity is further studied since it is considered as the practical application in rapid pavement repair in the field. The bond strength between old concrete and VFC modified concrete shows pretty promising results to apply in the bonded concrete overlay, though more extensive measurement of bond strength should be followed. The elastic modulus of VFC modified concrete was measured at early age and the value was smaller than typical elastic modulus of concrete.