Low cost system for measuring the evolution of mechanical properties in cement mortars as a function of mixing water

The water/cement ratio is a determining factor when making mortars since it depends on the adequate hydration of the cement so that the final mass reaches the desired strengths and the adequate workability of the material for subsequent handling. This paper presents a low-cost system based on resistive sensors of the Arduino platform, capable of reliably quantifying and in real-time, the loss of mix water that occurs in mortars through the hydration of the cement and the evaporation itself of water from its mix in a fresh state. Two types of aggregates have been used: natural and mixed recycling, and two dosages for each of them with cement/aggregate 1:3 and 1:4 ratios, where it has been possible to corroborate thanks to the sensor developed the differences in setting between these two types of mortars, and how the evolution of their mechanical properties over time is conditioned by the variation of the water content of mix. In this way, it has been possible to validate the measurement equipment developed to be used in the study of the evolution of setting in conglomerate materials. (C) 2020 Published by Elsevier Ltd.