Implementación de curvas de calibración esclerométricas para hormigones convencionales de las hormigoneras más importantes del Austro

Abstract

One of the most used non-destructive test for infrastructure evaluation and pathology is the rebound hammer. Its advantages include a considerable reduction in field-work, time and money. Although, the use of the standardized reference curve provided by the manufacturer is the common practice for concrete evaluation when using the rebound hammer, it is well known that its use to estimate in-situ compressive strength is not reliable. To achieve the necessary precision, the equipment must be calibrated for a specific mix/design, using a statistical significant number of samples. The overall objective of this research was to obtain and implement sclerometric calibration curves for the most used concrete types provided by two of the more important ready-mix plants in the southern part of Ecuador. The mentioned curves were obtained by correlating the compressive strength with the rebound hammer index (taken right before the compressive test was made). During testing the influence of the sample’s moisture content and the support/confinement conditions were analyzed. Results revealed that the moisture content in concrete specimens resulted in variations of 11.4%, decreasing the rebound indexes. This information was used to define correction factors for the calibration curves. Furthermore, it was found that the confinement conditions of the sample have no influence in the rebounds. Finally, by successfully obtaining the sclerometric calibration curves for the most used concrete types in the region, the goal of having a precise infrastructure evaluation is reached.