Abrasion of concrete

Abrasion of concrete is progressive loss of concrete mass due to mechanical degradation such as friction, grinding action, impact, overloading and local crushing. Vehicular movement and pedestrian traffic causes abrasion.  The worst effect of abrasion is caused by vehicle with studded/chain tyres. Similarly, in industrial buildings, the concrete floors are subjected to impact load and … Continue reading Abrasion of concrete

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Cavitation of concrete

Cavitation is a physical process that causes pitting of surface due to rise in local pressure by collapse of vapour bubbles. Cavitation can damage the concrete in following ways: (i) due to shock waves generated by bubble implosion;(ii) by the micro-jets due to bubble implosion;(iii) collapse of bubble clustersCavitation generally occurs in hydraulic channel and … Continue reading Cavitation of concrete

Impact of bad formwork in service life

Formwork are a crucial part of reinforced concrete (RC) design. It supports the concrete until concrete gains sufficient strength. Depending upon the shape, formwork can be as simple as a cubic box to as complected as spline surface.  While design of formwork is itself an major field of concrete engineering, here in this article, the … Continue reading Impact of bad formwork in service life

Leaching in water retaining structures

Without water cement cannot get hydrated. However after the hydration process has been completed, the presence of water can dissolve the hydration product and degrade the structure.  This is more true for water retaining concrete structures. In case of dam, the hydrostatic pressure coupled with water permeability can leach out the hydration product in unprecedented … Continue reading Leaching in water retaining structures

Leaching

Structures such as dam where the flow of water via pores of concrete is high, there could be significant loss of mono-sulfate and ettringite and decalcification of calcium silicate hydrate due to leaching out of these salts to the surface and subsequently washing away. This will lead to reduction in strength of concrete and increases … Continue reading Leaching

Durability of concrete in terms of water permeability

Permeability is one of the main indicator defining the durability of the concrete.  In one hand, the permeability of the concrete can be high from the beginning of concrete life, in which case, the deterioration takes place rapidly during the service life. While in the  other hand, the permeability of the concrete may gradually increases … Continue reading Durability of concrete in terms of water permeability

Controversial effect of Silica fume in concrete

Use of silica in concrete is one of the example that something that has been labeled as harmful can become a useful thing if we know its property in details. A branch of scientist are reporting that the Aggregate-Silica Reaction is responsible for deterioration of structure, while another group of researcher are using silica to … Continue reading Controversial effect of Silica fume in concrete

Alkali Silica Reaction (ASR)

The phenomenon of  aggregates reacting with alkali component of cement is called alkali aggregate reaction (AAR). The predominant form of alkali aggregate reaction is alkali- silica reaction (ASR) in which the silica content of aggregate reacts with sodium and potassium hydroxide of concrete. Other forms of AAR are alkali-carbonate reaction and alkali-silicate reaction. In China … Continue reading Alkali Silica Reaction (ASR)

Health of structure based on construction quality

RC structures has high degrees of variability during construction.  Often in most of the project, RC structures are casted in situ. Compared to steel structures, where most of the parts has quality control at the manufacturing plant, the construction practise of the RC structure has greater degree of uncertaininty in its strength and its performance. … Continue reading Health of structure based on construction quality

Basics of reinforced concrete deterioration

As the name suggests, reinforced concrete (RC) is composed of primarily two parts- concrete and reinforcement. Therefore, the deterioration of RC structure is mainly depended upon (a) concrete, (b) reinforcement and (c) physio-chemical interaction between them. Concrete is mixture of aggregates (sand, gravels) and binder (cement) and some admixtures (mineral or chemicals). And there are … Continue reading Basics of reinforced concrete deterioration