Análise da variação da resistência à compressão do concreto estrutural devido à perda de água na mistura do concreto no semiárido nordestino

Abstract

The study of concrete in its fresh state has fundamental importance to ensure quality in its hardened state because the concrete in the fresh state is more susceptible to actions that can compromise the performance of its properties such as dosing errors, manipulation, transportation, application, and its exposure to climatic factors such as temperature and humidity. The hot and dry climates favor the loss of mixing water due to the acceleration of the cement hydration reactions and evaporation. It is common especially in small constructions, the existence of a large time interval between the production and application of the concrete structure. After some time the concrete mix increases losing its consistency and workability, which necessitates the addition of water for the abatement correction. Excess water in the mix factor increases the water / cement ratio and reduces the strength of concrete. This paper aims to analyze the variation of consistency and compressive strength of the structural concrete caused by the action of intervening factors that are capable to change the concrete properties and that work in the concrete mix due to its time of exposure to ambient weather conditions in the northeastern semi-arid. This analysis was done through reduction tests and compressive strength, performed with samples of fresh concrete exposed for a variable time to actions of temperature and humidity recorded on site. From the analysis of the results it was concluded that the concrete produced in the city of Petrolina-PE had higher resistance in the winter period, characterized as warm and dry, and the lowest results was in the wetter month. In addition, it was concluded that the fresh concrete is influenced by climatic conditions in the region contributing to the reduction of resistance.