EXPERIMENTAL RESEARCH AND PREDICTION ON SHOTCRETE CREEP AT EARLY AGE

In order to grasp the creep performance of the early-age shotcrete used for the primary lining of a tunnel, creep experiments have been carried out with two different concrete mixes that are mostly used in tunnels of subway and highway respectively by simulating a typical construction environment. The strengths, shrinkage strains and compressive strains of specimens loaded at different ages are measured and the behavior of shotcrete creep at early age is investigated. The comparison between experiment results and predictive values of GL2000 and B3 are made and the main reasons for deviations between the experimental values and predictive values are analyzed. Finally, the pertinent modifications of the key parts of GL2000 are done and a new prediction model of shotcrete creep at early age is proposed.