Bond Performance of Advanced Environmentally Friendly Concrete Materials for Rapid Infrastructure Repair and Rehabilitation

Abstract

Portland cement production results in approximately 2.5 gigatons of direct CO2 emissions per year, or between 5% and 10% of human produced CO2 emissions. Calcium sulfoaluminate (CSA) cements are promising alternative hydraulic cements with nearly half the CO2 emissions during production and with high early strength (rapid setting) or controlled expansion (shrinkage compensating). These properties make CSA cement attractive and effective for transportation structure and pavement repair applications by increasing the speed of the repair and/or mitigating shrinkage cracking. Half of the bridges in the United States already have or will reach their anticipated design life in the next 10 years. Many can have their service life safely extended – with reduced environmental impact – by targeted repair and rehabilitation using CSA cements. Using concrete mix designs developed at the University of Oklahoma (OU) and the University of Arkansas (UARK), the ability of CSA cement to bond to traditional concrete substrates and the durability of those bonds over time were studied. The objectives of this study were to evaluate CSA cement concrete bond performance for varying substrate conditions, evaluate freeze-thaw durability of CSA cement concrete repairs, and to develop and communicate recommendations for CSA cement concrete repairs. The results of the study suggest that the tensile bond strength between CSA cement concrete and ordinary portland cement (OPC) concrete is generally sufficient and, in some cases, may surpass the tensile strength of the OPC concrete. The freeze-thaw durability of these repairs is generally sufficient as well. Therefore, relative to tensile bond strength and resistance to freeze-thaw deterioration, CSA cement concretes have proven to be a feasible option for rapid infrastructure repair.