Durability of calcium-aluminate based binders for rapid repair applications
MetadataShow full item record
Within the last few decades, the amount of vehicle miles traveled within the US has increased approximately 40% with the construction of new roads only increasing 4% during this same time period. This dramatic increase in traffic on existing infrastructure has led to the rapid decline of the condition our nation’s roads resulting in the increased need for maintenance and repair. Rapid hardening repair materials are in high demand for these applications as they allow for minimal traffic delays and road closures. Calcium aluminate cement (CAC) is a rapid hardening binder that is used for specialty applications where high early strength and increased durability are desired. In recent years, blended cement systems incorporating both CAC and calcium sulfate (C$) with portland cement (PC) have been developed to utilize the rapid hardening characteristics of CAC but at a reduced cost. While the durability of CAC is well researched and documented, the durability of these new blended systems is not yet fully understood. The focus of this research was to evaluate the performance and long term durability of various blended systems which utilize CAC or calcium sulfoaluminate cement (CSA) to attain rapid hardening. More specifically, these systems were evaluated to determine their resistance to common modes of concrete deterioration such as alkali-silica reaction, external sulfate attack, delayed ettringite formation, carbonation, and corrosion in marine environments through in-situ lab methods and large scale outdoor exposure. The results of the testing conducted related to alkali-silica reaction, external sulfate attack, and delayed ettringite formation identified the potential for large levels of expansion in blended systems of PC:CAC:C$ and PC:CSA. Details regarding each mode of deterioration and mechanisms of expansion are discussed.