Application of the Maturity Method to Belitic Calcium Sulfoaluminate Cement Concrete

This study investigates the applicability of the maturity method to concrete made with belitic calcium sulfoaluminate (BCSA), a type of cement known for its rapid strength gain. The research aims to assess the accuracy of strength prediction using the maturity method under varying curing temperatures and citric acid (CA) dosages and to suggest modifications to the maturity approach needed for BCSA cement. A maturity approach is valuable for fast-setting, fast-strength gain materials since they are often used for their early-age strength, but the speed of strength development may make destructive testing at these early ages difficult. The datum temperature for BCSA cement strength development was determined experimentally and found to range from −0.88°C to −1.76°C (30.41°F to 28.83°F), depending on CA content. The activation energy ranged from 54.2 kJ/mol to 57.5 kJ/mol, aligning with literature-reported values. Using these values, maturity curves were developed using the Nurse-Saul function, and benchmark logarithmic equations were derived from controlled laboratory tests. Next, 17 specimens from BCSA cement concrete mixtures were prepared with and without CA cured across a wide temperature range [0°C (32°F) to 34°C (94°F)] in non-temperature-controlled environments to simulate field conditions. When applied to field-cured specimens, the maturity method predicted early-age compressive strength with an accuracy of approximately ±10% within a 50–6,000°C-hours maturity index range, corresponding to about 7 days of age. Very early age estimates were more variable. These findings demonstrate that the maturity method provides a reliable and practical means of estimating early-age strength in BCSA concrete mixtures, enabling more accurate on-site assessments and construction decision-making in fast-track applications.