Factors Affecting the High Early Strength Development and the Methods for Testing High Early Compressive Strength of the Rigid Pavement

Maintenance highway rigid pavement can cause a significant impact on traffic congestion due to the lack of the traffic lane. Typically, the general maintenance plans are arranged from midnight to early morning before the morning peak traffic periods to mitigate the possibility of traffic congestion. As a result, to open to traffic, the maintenance highway rigid pavement usually requires the concrete to meet a compressive strength requirement of 210 kgf/cm² after 4–6 h. The high early strength mix design (S-mix design) is examined and published by the Taiwan Freeway Bureau, MOTC. However, this research shows that the S-mix design's early compressive strength is significantly affected by the exterior temperature. Therefore, it is practically important to control the temperature at the early ages of the concrete. In addition, the maturity method and rebound hammer test results can be used to evaluate high early compressive strength of the construction site. Due to the rigid pavement requires high early compressive strength in a short period of time, taking the specimen to the laboratory to conducting the compressive strength test is challenging. Thus, using the rebound hammer result to simulate the hydraulic compressive testing value is one of the suitable method for evaluating high early compressive strength of the construction site. The method for testing the high early compressive strength of the rigid pavement is analysis of the correlation between rebound hammer test results and the hydraulic compression testing value, creating the S-mix design, then establish the maturity index value of the S-mix design.