Reinforcement corrosion will produce iron oxide and hydroxide on steel bar surface, consequently its volume increases.

assign proper cross section for the concrete element.

Provide compression reinforcement if possible.

Use minimum possible quantity of water.It is mainly the external walls especially thin walls exposed to direct solar radiation and the roof which are subject to substantial thermal variation that are liable to cracking.įig.4:concrete building cracks due to creep movement Thermal variations in the internal walls and intermediate floors are not much and thus do not cause cracking. The thermal movement in a component depends on a number of factors such as temperature variations, dimensions, coefficient of thermal expansion and some other physical properties of materials. All materials more or less expand on heating and contract on cooling.Īmbient temperature changes and loss of heat of hydration in portion of structure at different rate lead to temperature variations and subsequent thermal movement. Thermal movement is one of the most potent causes of cracking in buildings. The above discussion suggests suitable measure to decrease concrete permeability and hence cracks. The permeability of cement paste is a function of water-cement ratio given good quality materials, satisfactory proportioning and good construction practice the permeability of the concrete is a direct function of the porosity and interconnection of pores of the cement paste. The first three are allied to the concrete strength as well. There are number of factors that controls concrete permeability like water-cement ratio, use of admixtures, curing, air voids due to deficient compaction, micro-cracks due to loading, cyclic exposure to thermal variations, and age of concrete. Therefore, low permeability is a key factor to concrete durability. it dictates the ability of concrete to withstand weathering action, chemical attack, or any process of deterioration.

Improper structural design and specificationsĪs deterioration process in concrete begins with penetration of various aggressive agents.The principal causes of cracks in a building are as follows: Improper Structural Design and Specifications

Silo 2 crack