Performance of Portland Cement-Based Rapid-Patching Materials with Different Cement and Accelerator Types, and Cement Contents

Because of the requirements of opening pavement to traffic after placing repair concrete, it is essential for that concrete to achieve high early strength. To ensure this, a high cement content is generally used in Portland cement-based rapid-patching materials. Besides its associated high cost, high cement content tends to result in a less stable mix with high drying shrinkage, high autogenous shrinkage, high heat of hydration, and cracking potential. In addition, using chloride-based accelerators has adverse effects on concrete durability. Therefore, this paper presents an experimental assessment to improve rapid-patching concrete mixtures by reducing cement content through optimizing aggregate gradation. A non-chloride-based accelerator was also sought to replace the chloride-based accelerator when the accelerators are associated with two different series of patching materials using Type I and III cement, respectively. Fresh, early-age, mechanical, and permeability tests were conducted on each specific mixture design. As an important outcome, patching materials employing lower cement content together with an optimized aggregate gradation can meet the general requirements, which were found from the observation of several key parameters, including early-age strength, setting times, surface resistivity, and heat of hydration. Furthermore, the non-chloride-based accelerator showed promising behavior as an alternative accelerator when it is blended with the proper cement type and content.