Influence of increasing fresh concrete and concrete hardening temperatures on concrete properties

The influence of climate change is manifested in a steady increase of days with hot weather conditions, which significantly increases the probability of elevated fresh concrete temperatures (>30 degrees C) during the production, placement and hardening of the concrete. Such climatic conditions represent a challenge for concrete construction, due to the fact that without energy- and CO2-intensive countermeasures, such as cooling the raw materials, an increase in the temperature of the concrete during processing and hardening is highly to be expected. This leads to an influence on hydration, which usually manifests itself in an accelerated decrease in workability and a reduction in mechanical properties and durability. The aim of this article is to gain a better understanding of the influence of increased fresh concrete temperatures on the above-mentioned properties. Furthermore, the influence of the so-called hardening temperature - the ambient temperature up to the concrete age of three days - on the concrete properties was investigated. For this purpose, temperatures up to 40 degrees C were investigated.