Effects of Superplasticizers, Retarders, and Workability Retention Admixtures on the Fresh and Hardened Properties of Concrete

Abstract

Currently, maintaining the quality of ready-mix concrete during long-distance transportation is challenging, as climatic variations affect its properties. To address this issue, the use of next-generation admixtures is proposed to enhance both the physical and mechanical properties of concrete in its fresh and hardened states, employing superplasticizers (S), retarders (R), and workability-retaining agents (M). Among the tested mixtures, D0.54%S0.48%R1.01%M exhibited the best performance by maintaining its consistency for up to 7 hours and extending workability by an additional 6 hours compared to the reference sample. Furthermore, with the use of R and M admixtures, this sample achieved a final setting time of 13 hours and 21 minutes—a 331% increase relative to the reference—and demonstrated one of the highest compressive strengths, reaching 45.39 MPa after 28 days. The unit weight and yield results indicate that the concrete falls within the normal-weight category, although these values may vary with atmospheric conditions. In conclusion, next-generation admixtures effectively preserved consistency and extended setting time during prolonged transportation, while significantly enhancing compressive strength at 3, 7, and 28 days.