Quality evaluation of shotcrete by acoustic emission

Shotcrete is known to have high strength, good durability and limitless shape possibility, and is normally applied to repair and restoration of concrete structure and often employed for ground support. In order to improve the placement and the strength of shotcrete, fly ash is mixed. In order to investigate the quality of hardened shotcrete with fly ash, acoustic emission (AE) technique is applied. After detecting AE date, Damage Estimation of Concrete by Acoustic Emission Technique (DeCAT) and a normalized AE activity are taken into consideration. It is found that the compressive strength of shotcrete with fly ash of class 1 is higher than that of shotcrete with ordinal Portland cement. Relative damages estimated by DeCAT show the improvement of quality of shotcrete with fly ash of class 1. Distribution on the normalized AE activity derives a clear deference between shotcrete and ordinary concrete.