Previsão da resistência à compressão de concretos pelo método da maturidade: influência do tipo de cimento e cura

Abstract

The need for continuous monitoring of concrete structures is extremely important, since the technician in charge, often, does not have the availability to be full time on the work to verify all construction processes. In addition, after the execution of structures and/or concrete elements, carrying out destructive tests becomes unfeasible. On the other hand, non-destructive tests that help in the analysis without affecting the structure or executions that have already been carried out, do not provide accurate results of concrete strength. To reduce these errors, a method that helps to determine the final strength of a concrete in situ is the use of sensors and the maturity method. This method makes it possible to predict the compressive strength of concrete through the relationship of time and temperature. Thus, this work presents a study on the maturity method using the same mix for two types of cement (CP IV and CP V ARI RS) and two types of curing (laboratory environment and submerged in water). The objective is to obtain compressive strength curves by the time-temperature factor (maturity index) in order to estimate the strength of concrete at any desired age for different conditions. To carry out the tests, cylindrical specimens measuring 100mm x 200mm were used, divided between monitoring the internal temperature continuously until the age of 28 days, and broken specimens at the ages of 1, 3, 7, 14 and 28 days. Therefore, Arduino was used to collect the data. As a result, it was possible to verify how the type of cement and the type of cure can influence the compressive strength of concrete. Finally, to estimate the compressive strength of concrete at work in typical winter seasons, using the same trace studied, it is indicated the use of curves considering ambient curing for CP IV and submerged curing for CP V, thus obtaining resistance values about 13% underestimated, in favor of the safety of the monitored concrete structure. Keywords: concrete compressive strength, temperature sensor, maturity method, Arduino.