Construction Technology
DECAY AND DRTERIORATION OF BUILDINGS
CAUSES OF OCCURANCE OF CRACKS
The important causes responsible for occurrence of cracks in buildings, are as under: 1) Cracks due to moisture changes. 2) Cracks due to temperature variation. 3) Cracks due to elastic deformation and creep. 4) Cracks due to effect of chemical reaction. 5) Cracks due to movements of ground. 6) Cracks due to vegetation.
The various causes of formation of cracks and measures adopted to prevent them are described below: 1) Cracks due to moisture changes.
We know that most of the building materials like bricks, concrete, mortar, stone, timber etc. have pores. Hence these materials increase in size or expand on absorbing moisture and decrease in size or shrink on drying.
Shrinkage on account of drying out of moisture contents in building materials is one of the main factors responsible for cracks in the buildings.
Shrinkage cracks normally appear in weak-sections of the masonry such as door, window openings, staircase wall etc. such cracks are uniformly and regularly placed. The formation of shrinkage cracks in masonry depends upon the type of material used in the masonry and the strength of the mortar. 2) Cracks due to temperature variation
We know that almost all materials expand on heating and contract on cooling. In some materials the changes in temperature can cause appreciable variation in the building components depends upon a number of factors such as dimensions of the materials, its coefficient of expansion, the magnitude of variation in the temperature etc. The effect of temperature variation in the internal walls and intermediate floors is very small and may not result in cracks. On the other hand effect is appreciable on the external walls and roof which is directly exposed to sun. 3) Cracks due to elastic deformation and creep
The different components of the building viz. wall, column, beam, slab etc. undergo elastic deformation when loaded. The
CAUSES OF OCCURANCE OF CRACKS
The important causes responsible for occurrence of cracks in buildings, are as under: 1) Cracks due to moisture changes. 2) Cracks due to temperature variation. 3) Cracks due to elastic deformation and creep. 4) Cracks due to effect of chemical reaction. 5) Cracks due to movements of ground. 6) Cracks due to vegetation.
The various causes of formation of cracks and measures adopted to prevent them are described below: 1) Cracks due to moisture changes.
We know that most of the building materials like bricks, concrete, mortar, stone, timber etc. have pores. Hence these materials increase in size or expand on absorbing moisture and decrease in size or shrink on drying.
Shrinkage on account of drying out of moisture contents in building materials is one of the main factors responsible for cracks in the buildings.
Shrinkage cracks normally appear in weak-sections of the masonry such as door, window openings, staircase wall etc. such cracks are uniformly and regularly placed. The formation of shrinkage cracks in masonry depends upon the type of material used in the masonry and the strength of the mortar. 2) Cracks due to temperature variation
We know that almost all materials expand on heating and contract on cooling. In some materials the changes in temperature can cause appreciable variation in the building components depends upon a number of factors such as dimensions of the materials, its coefficient of expansion, the magnitude of variation in the temperature etc. The effect of temperature variation in the internal walls and intermediate floors is very small and may not result in cracks. On the other hand effect is appreciable on the external walls and roof which is directly exposed to sun. 3) Cracks due to elastic deformation and creep
The different components of the building viz. wall, column, beam, slab etc. undergo elastic deformation when loaded. The