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Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1]
Concrete has very favourable properties in fire – it is not adversely affected by fire until it reaches very high temperatures. It also has very high mass, so it is good for providing sound insulation and heat retention (leading to lower energy requirements for the heating of concrete buildings).
It not only seals the cracks but also partially or entirely recovers the mechanical properties of the structural elements. This kind of concrete is also known as self-repairing concrete. Because concrete has a poor tensile strength compared to other building materials, it often develops cracks in the surface. These cracks reduce the durability ...
A single concrete block, as used for construction. Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2]
CTLGroup's experts, having studied the physical properties of concrete made with lunar soil, [13] also referred to as lunarcrete, had conceived of building space stations and other structures on the moon using lunar soil. In their research the lunar material was conceived as a cementitious substitute that would help minimize supplies to be ...
An ultrasonic pulse velocity test is an in-situ, nondestructive test to check the quality of concrete and natural rocks. In this test, the strength and quality of concrete or rock is assessed by measuring the velocity of an ultrasonic pulse passing through a concrete structure or natural rock formation.
When used in the generic sense, this is the material referred to by the term "concrete". For a concrete construction of any size, as concrete has a rather low tensile strength, it is generally strengthened using steel rods or bars (known as rebars). This strengthened concrete is then referred to as reinforced concrete. In order to minimise any ...
The bond strength of vacuum concrete is about 20% higher. The surface of vacuum concrete is entirely free from pitting and the uppermost 1/16 inch is highly resistant to abrasion. These characteristics are of special importance in the construction of concrete structures which are to be in contact with flowing water at a high velocity.