Poor construction practice cracking

A wide variety of poor construction practice results in cracking in concrete structures. Among these, the most common practice is to add water to concrete to increase its workability. Others are lack of curing, inadequate consolidation, inadequate formwork supports and placement of construction joints at points of high stress. Additionally, by adding cementitious material, even if the water/cement ratio remains constant, more shrinkage will occur because the paste volume is increased (ACI 2007). 

Inadequate curing before opening the pavement to traffic may result in concrete with poor skid resistance owing to loss of surface mortar. Areas with heavy traffic or lanes for commercial vehicles are going to suffer first. 

To avoid poor construction cracking, simply follow precisely and strictly the instructions and specifications provided. 

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Fig. 28.6. Fatigue data for welded joints in clean air. The class given to a weld depends critically on the weld detail and the loading direction. Classes B and C must be free from cracks and must be ground flush with the surface to remove stress concentrations. These conditions ore rarely met in practice, and most welds used in general construction hove comparatively poor fatigue properties.

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