Even if concrete is the most and widely used material for construction, it also has its limitations. However, some of those limitations can be corrected by modifying the concrete by adding other ingredients. In this article we are going to focus on those disadvantages that probably can make concrete unsuitable for construction.
Toughness can be defined as the ability of any material to withstand impact energy. Concrete has a low toughness compared to other materials such as steel. In fact, concrete toughness is about 2% of steel.
Formwork must be used
The state of a fresh concrete is liquid. Therefore, a formwork is required to mould the concrete in a shape and also to support its weight. The formwork can be expensive to procure and install. Also, installing consumes time and it is labor intensive. Prefabrication and precast are some of the measures adopted to overcome this.
Takes a long time to cure
For concrete to attain compressive strength, it requires about 28 days of curing and casting. Its full strength is achieved in controlled temperatures for a period of over a month. Steam curing or microwave curing can be used to overcome this problem.
Concrete requires use of skilled labor during mixing, curing and placing. For superior and quality concrete, each step must be handled with great care lest you get the concrete which has performance issue and of poor quality.
This is the ratio of strength to density. Concrete has got half specific strength of that of steel. Specific strength is controlled by increased strength and decreased density. High strength and lightweight concrete mitigate this problem.
Concrete has different tensile and compression strength. As a matter of fact, concrete tensile strength is 1/10 of its compressive. Polymers and fibers are used in order to increase the concrete tensile strength.
It is a brittle material
The major causes of material failure is brittleness, which can be classified to
- Quasi brittle failure
- Ductile failure
Mild steel and glass experience brittle and ductile failure respectively. The materials fail when the tensile strength is arrived at. Unlike other materials, concrete shows a strain softening behavior. Such materials are said to exhibit quasi brittleness.
The concrete making process is mainly divided into 5 parts. Every step has it’s own importance and learning the whole process is important to understand what’s the strength of concrete is.