Durable High Early Strength Concrete Mixtures for Pavement Repair

While calcium chloride accelerators are widely used, other accelerators are also available and may be able to address some of the shortcomings of using calcium chloride accelerators. The proposed research has 2 primary objectives: (1) to evaluate other hydration accelerating products for concrete durability and (2) to develop an optimized set of mixture parameters for durable high early strength concrete. The most promising mixtures from KSU-17-2 will be utilized as candidate mixtures and several commercially available accelerating admixtures will be utilized in place of the calcium chloride accelerator. Candidate accelerating admixtures include Daraset 400 (GCP), Sika Rapid-1, and MasterSet AC534 (BASF). For each concrete mixture, several laboratory tests will be performed. Drying shrinkage testing, Surface Resistivity, time resolved compressive and flexural strength will all be evaluated. Durability testing according to KTMR-22 will be conducted on these mixtures. In addition to the hardened properties, fresh air content and SAM number as well as mixture slump will be measured and recorded. With the impact of different accelerators assessed, the research will focus on developing an optimized repair mixture. It is expected that lower cement contents will result in improved durability owing to reduced shrinkage and thus shrinkage microcracking. Furthermore, techniques to achieve a repeatable, stable air void system (according to the SAM number) will be investigated. Promising mixture designs and mixture concepts will be documented and proposed for reproduction in Kansas Department of Transportation (KDOT) laboratories to ensure repeatability of mixture strength gain characteristics and durability.