Compressive Strength and Durability

**91**

**Chapter 5**

**Abstract**

values.

**1. Introduction**

various environmental conditions [6].

*Alireza Farzampour*

Compressive Behavior of Concrete

Concrete strength is fairly sensitive to environmental effects. Extreme weather conditions and changes in humidity rates significantly affect the concrete compressive strength development. Concrete as one of the substantial material used in residential buildings and infrastructures is subjected to a massive strength change under extreme weather conditions. For understanding, the different concrete's behavioral aspects, various commercial cement types under different temperatures, and humidity rates are investigated in this chapter. The experiments are aimed to investigate the concrete strength development over time when the material is cast at lower to mild temperatures and different humidity index rates. Results show that reducing the curing temperature more than 15° could result in 20% reduction in total compressive strength, while decreasing humidity rates by 50% leads to less than 10% drop in ultimate strength. To understand the strength developing process, maturity tests are conducted. It is shown that concrete is not able to reach to the expected ultimate strength if the temperature is significantly low regardless of curing time. The effect of temperature change during the curing process is more tangible on strength development compared to cement type and humidity rate

**Keywords:** compressive strength, environmental effects, maturity, durability

There is significant need for evaluating the concrete behavior on-site without implementing experimental tools. Concrete if properly placed in extreme weather conditions is able to develop desired ultimate strength [1]. Temperature changes could cause cracks or sapling, distress, and aggregate expansion which leads to concrete strength deterioration. Many different procedures are recommended in codes to reduce the negative effects of low or high ambient temperature [1, 2]. High temperature, above 100°C, could lead to color changes in aggregates leading to abrupt loss of compressive strength. While, lower temperature, less than zero, usually ends up in cracking and low resistance against freeze-thaw effects [3–5]. A common practice to reduce the undesirable crack propagation in concrete mixtures under thermal effects is to use fibers due to having persistency in behavior under

The behavior of the concrete under high temperature values could be affected with several factors. The temperature rate, aggregate type, and stability of the mixture are among the most important factors to be considered under high temperature condition. It is noted that the abrupt temperature rise can cause thermal

under Environmental Effects
