When concrete is permeable it can cause corrosion in reinforcement in presence of oxygen, moisture, CO2, SO3- and Cl- etc. This formation of rust due to corrosion becomes nearly 6 times the volume of steel oxide layer, due to which cracking develops in reinforced concrete and spalling of concrete starts. So, if the concrete is(…)
How To Guide
CONCRETE CUBE TEST RESULTS ACCEPTANCE
ACCEPTANCE OF CONCRETE CUBE TEST RESULTS ACI-5.6 2008 requires that all the tests to be performed on fresh, hardened or old concrete are to be performed by qualified field testing technicians. They should collect and prepare all the specimens for testing and should record temperature and other important information about the fresh concrete. 1. Frequency(…)
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 (…)
CEMENT GROUTING FOR CRACKS IN CONCRETE AND MASONRY
Cement Grouting in cracks in concrete and masonry: Wide cracks, particularly in mass concrete abutments / piers and masonry substructures can be repaired by filling with portland cement grout. This method is effective in sealing the crack in concrete, but it will not structurally bond cracked sections. Applications of cement grouting: i) When cracks are(…)
REPAIR OF ACTIVE CRACKS IN CONCRETE
Methods of Repairing Active Cracks in concrete structures: 1. Drilling and Plugging through Crack: One of the approximate methods would be to drill holes normal to cracks, fill them with a suitable epoxy or epoxy-mortar formulation and then place reinforcement bars (of predetermined sizes and lengths) in them to stitch across the cracks. The bars (…)
NEED AND TYPES OF INSPECTION OF CONCRETE STRUCTURES
NEED FOR INSPECTION OF CONCRETE STRUCTURES: Inspection is the first step towards any maintenance programme. The purpose of structural inspection can be classified as under: i) To provide assurance that the concrete structure is structurally safe and fit for it’s designed use. ii) To identify actual and potential sources of trouble at the earliest possible(…)
RECOMMENDED CONCRETE MIXES FOR VARIOUS CONSTRUCTION
RECOMMENDED CONCRETE MIXES FOR VARIOUS TYPES OF CONSTRUCTION WORKS: Type of work App. Concrete Mix Max. size of aggregates (mm) Water for one cement bag batch (ltr) Total for dry aggregates For aggregates condition from dry to moist Best consistency Small precast work, fence posts, poles, garden furniture and other work of very thin sections(…)
MEASURING REINFORCEMENT CORROSION IN CONCRETE
There is need to know the extent of corrosion in pre-stressing steel as well as that of reinforcing steel in concrete. No instrument / technique is available, at present, which can measure the extent of corrosion of steel. However, measurement of concrete properties, such as resistivity and potential of concrete can assess the probability of(…)