Concrete Cracks

REPLACEMENT CONCRETE: MATERIALS AND APPLICATIONS

Replacement concrete is a method of repair for defective concrete when the defects or cracks in concrete have large area. In this method of concrete repair, defective concrete is removed from the structural member and area is prepared for repairs and then replacement concrete is used. Concrete repair using this method is used when the(…)

CAVITATION DAMAGE IN CONCRETE AND PROTECTION

Cavitation damage on concrete surface is most common in case of spillway in dams. This leads to cracks on the concrete surface which further increases the risk of damage to concrete by means of sulfate attack, freeze-thaw, alkali-silica reaction and other means. Cavitation damage occurs on concrete surface when discontinuity or irregularities is encountered in(…)

STEPS FOR CONCRETE DAMAGE REPAIRS IN STRUCTURES

Repair of concrete is needed time to time as the structure gets old due to several reasons. We will discuss the steps involved in the process of repair of concrete structures. Following are the steps involved in the repair of damaged concrete: 1. Determination of cause of Concrete defects: The first and important step for(…)

TYPES OF CRACK IN CONCRETE STRUCTURES

Types of cracks   Structural cracks. Non Structural Cracks. Structural Cracks Structural cracks are those which result from incorrect design, faulty construction or overloading and these may endanger the safety of a building and their inmates. Non Structural Cracks. Non Structural cracks occur mostly due to internally induced stresses in building materials. These cracks normally(…)

PREVENTION OF PLASTIC SETTLEMENT CRACKS

Prevention of plastic settlement cracking The restraints that cause plastic settlement cracking are inherent in the construction and generally cannot be avoided. Abrupt changes in section depth could be avoided at the design detailing stage but the main reduction of risk is through mix design and suitable cohesion of the concrete to reduce bleeding. In(…)

CONCRETE CRAZING AND PREVENTION

Concrete Crazing: Crazing is the development of a network of fine random cracks or fissures on the surface of concrete caused by shrinkage of the surface layer. These cracks are rarely more than 3mm deep, and are more noticeable on over floated or steel-troweled surfaces. The irregular hexagonal areas enclosed by the cracks are typically(…)

TYPES OF CHEMICAL ATTACKS ON CONCRETE STRUCTURES

Chemical attacks on concrete structures causes deterioration of structure and its durability is affected. The life of structure reduces and it can lead to failure of structures. The various types of chemical attacks and their effects on concrete structures are discussed below: (a) Chlorides attacks on concrete structures: High concentrations of chloride ions cause corrosion(…)

REDUCING DRYING SHRINKAGE IN CONCRETE

Shrinkage of concrete from Drying The common cause of cracking in concrete is shrinkage due to drying. This type of shrinkage is caused by the loss of moisture from the cement paste constituent, which can shrink by as much as 1% per unit length. Unfortunately, aggregate provides internal restraint that reduces the magnitude of this(…)

BUILDING CRACKS- CAUSES & REMEDIES

Causes of Cracks in concrete structures: The principal causes of occurrence of cracks in a building are as follows: 1. Permeability of concrete. As deterioration process in concrete begins with penetration of various aggressive agents, low permeability is the key to its durability. Concrete permeability is controlled by factors like water-cement ratio, degree of hydration/curing,(…)

GROUTING PROCEDURE FOR CRACKS IN CONCRETE

Procedure for cement grouting of cracks in concrete structures: Holes  are  drilled  in  structure  along  cracks  and  in  an  around  hollow spots.  If  there  are  several  cracks,  holes  can  be  drilled  in  a staggered  manner  at  500  to  750mm  spacing  in  both  directions covering  adequately  the  area  proposed  to  be  grouted.  Holes spacing  can  be (…)