ASSIGNMENT concrete basement which was destroyed by fire.The extensive

                                                         ASSIGNMENT -1                                                   Fire Damage                                                                                  Source:                 The figure shows the concrete basement which was destroyed by fire.The extensive heat due to fire caused the affected area to expand extremely. The difference in expansion in layers of concrete produced stresses and reducing the compressive strength of the concrete, because of which spalling occurred and eventually, led to the deterioration of the concrete. The material properties also changed at a higher temperature.                                                                                                                              Corrosion                                                          Source: Personal Inspection.        Corrosion of the reinforced concrete stairs at the campus of university of ottawa occurred. The naturally occurring process, generally, takes place slowly on the set of electrochemical reaction. The corrosion is due to the severe cold weather and freeze and thaw conditions, resulting in degradation of the concrete. Earthquake                Source:            The photograph is of the damaged column in a three storey RC school building as a result of the earthquake in Shitigahama town. The column got affected because of the shear failure occurrence in it.             Shrinkage CrackingSource: Personal Inspection            The cracks were noticed on the concrete pavement. The loss of moisture from the surface exposed to environment, results in reduction of volume and causes shrinkage. Due to the moisture difference between the surface exposed to environment and the surface underneath, the stresses occur and on exceeding the tensile capacity of concrete produced cracks in it. Thermal Cracking                   Source :                   The thermal cracking seen in the reinforced concrete cylindrical tank which was under construction. As the concrete heats up because of reaction between cement and water, it expands. On cooling, the restraint to contraction causes the tensile stresses. The wider vertical cracks are produced on the surface of the tank.                                                                                                                                    Chemical AttackSource:          In photograph, the corrosion took place in grit removal tanks in a wastewater treatment plant that was constructed in 2003. The aggregates are even visible above the water line. The deterioration of the concrete occurred due to the presence of various chemicals in water of the sewer system.                              Alkali Silica Reaction DamageSource:                      The cracks produced in the pavement are due to the alkali silica reaction in the concrete. ASR is the very common type of alkali aggregate reaction. The silica mineral reacted with the alkali content of concrete to form gel which expanded and caused stresses, thus developing cracks and resulting in significant damage to concrete and need to given an immediate repair.                                    Alkali Carbonate Reaction DamageSource:             The deterioration is seen due to alkali carbonate reaction in New Jersey. ACR is the rare type of alkali aggregate reaction. The cracking took place because of the reaction between reactive carbonate aggregates and very high alkali content and that caused dedolomitization as well as the expansion of the affected particles of aggregates, hence, producing stresses and cracks.                                Delayed Ettringite Formation DamageSource:               Theses cracks were developed in Swedish concrete railroad ties. DEF was the affecting mechanism in it.The formation of delayed ettringite, resulted in expansion and exertion of pressure in the concrete, giving rise to cracks. It was found that along with the temperature, other factors like cement composition, fineness etc. were the influencing parameters that led to delayed ettringite formation in concrete.         Freeze and Thaw      The staircase is damaged severely due to freeze and thaw cycle. The repetition of the cycle in concrete in the  lower portion of the stairs, created stresses due to expansion when water freezes,as a result of which the concrete became weak with significant reduction in compressive strength and ultimately disintegrating it.Source:                                                Scaling   The photograph shows the severe scaling on wall of concrete foundation of a residential building. The occurrence of deterioration is due to the freeze and thaw process particularly in cold environments.The stresses due to solid ice formed led to damaging of concrete.Source: damage in field conditions and Protective Sealer and Coating Systems


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