Title: Suitability of CPC-18 and Carbonation of Specialty Cementitious Systems
Author(s): Gokul Dev Vasudevan and David Trejo
Publication: Materials Journal
Appears on pages(s): 79-90
Keywords: calcium aluminate cement (CAC); calcium carbonate content; calcium sulfoaluminate cement (CSA); carbonation; carbonation front; ordinary portland cement (OPC); thermogravimetric analysis (TGA); water-cementitious materials ratio (w/cm)
Carbonation of concrete systems can result in corrosion of the steel reinforcement. The International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM) Concrete Permanent Committee-18 (CPC-18) test method is commonly used to determine the carbonation depth of ordinary portland cement (OPC) systems. However, the standard does not clearly state whether this test is appropriate for specialty cementitious systems such as calcium aluminate cement (CAC) and calcium sulfoaluminate cement (CSA). Thermogravimetric analysis (TGA), on the other hand, is a proven test method to determine the carbonation front of all cementitious systems. This study assesses the reliability of CPC-18 by comparing CPC-18 test results with TGA results for carbonated OPC, CAC, and CSA systems. Results indicate that CAC and CSA systems carbonate faster than OPC systems, and the CPC-18 method can be used for testing the carbonation depth of CSA systems. However, the CPC-18 test method produces a less distinct color in CAC, which could lead to higher variability in results.