22-10-2016, 04:06 PM
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INTRODUCTION
Why crack are developed in RCC building ?
1)Cracks in buildings are of common occurrence. A building component develops cracks whenever stress in the component exceeds its strength. Stress in a building component could be caused by externally applied forces, such as dead, live, wind or seismic loads, or foundation settlement or it could be induced internally due to thermal variations, moisture changes, chemical action, etc.
2)Faulty design, bad quality materials, wrong method of construction, weather effects and lots of wear and tear can create cracks in walls, floors and ceilings
3) Cracks are harmful for the building and also for human life
4)That’s why we want to repair the cracks developed in the building and also wants to prevent the cracks before development.
Types of cracking
- Pattern Cracking:
- D-Cracking:
- Shrinkage cracking:
- Plastic cracking:
- Settlement cracking:
- Structural cracking:
- Tension cracking:
- Rust cracking:
- Thermally-induced cracking:
Prevention of cracks in concrete work
Good construction practices and techniques should be followed to prevent occurrence of structural damages that may occur during occupancy and with age of the structure. A structure has to go through different stages in construction process. Each and every stage of construction is important to make sure that the structure being constructed will not experience damage under any general circumstances. Development of cracks in structure is the first sign of damage.
Following are the good construction practices and techniques on which we want to concentret when doing canstruction
1)Masonary work
2)Concrete work
3)RCC frame work
4)Plastering
5)Concrete terazzo floor
6)RCC lintel
7)RCC roof slab
8) Provision of glazed, terrazzo or marble tile on vertical surface
9) Finish on wall
10) Pace of construction
11) Provision of reinforcement for thermal stresses
12) Extension of existing building
13) Rich cement treatment on external walls
14)Movement joints
15) Filling in plinth
Repairs of ckacks in in RCC structure
a suitable methods of concrete crack repair procedure can be selected. Successful repair procedures take into account the cause of the cracking. For example, if the cracking was primarily due to drying shrinkage, then it is likely that after a period of time the cracks will stabilize. On the other hand, if the cracks are due to a continuing foundation settlement, repair will be of no use until the settlement problem is corrected.
Following is a survey of crack repair methods, including a summary of the characteristics of the cracks that may be repaired with each procedure, the types of structures that have been repaired, and a summary of the procedures that are used.
SCOPE OF WORK
Cracks can be treated as cancer in R.C.C structure, as cancer which in its primary stage is curable to a certain extent but becomes danger to life in later stage; same happens with cracks.
We want to carry out suitable repairs and remedial measures. For repairs and remedies to be effective, it is essential that the engineer should have a proper understanding of various causes of occurrence of cracks. For investigating the causes it is necessary to observe carefully the location, shape, size, depth, behavior and other characteristics of the cracks, and to collect information about specifications of the job and time of construction.