This test helps in determining the suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required strength, durability, and workability as economical as possible is termed as concrete mix design. It involves studying properties of Aggregate, Cement, Water & Admixture (if any), and is used to determine the proper Concrete Mix Design.
Test Method: IS: 10262
Ultrasonic concrete testing is based on the pulse velocity method to provide information on the uniformity of concrete, cavities, cracks and defects. The pulse velocity in a material is directly proportional to its density and its elastic properties which in turn depends on the compressive strength and the quality of the concrete. It is, therefore, feasible to obtain information about the properties of components by sonic investigations.
Test Method: IS 13311 (Part 1)
Measuring the calcium chloride content of concrete is used to determine the dryness of concrete. This test is useful to tell if the concrete is ready for projects such as installing flooring on top of the concrete slab. Though some conditions can alter the results, such as the seasons of the year, the porosity of the concrete, or the mixture of the concrete, a calcium chloride test serves as a good indicator of the usability of concrete.
Test Method: IS: 6925-1973
The chloride permeability of concrete subjected to static and repeated compressive loading is evaluated by using this test method. The test results indicate that the chloride permeability of concrete subjected to static and repeated loading at a gradually increasing rate and its residual strain. This test covers the determination of the electrical conductance of concrete to provide a rapid indication of its resistance to the penetration of chloride ions.
Test Method: AASHTO T277
Chloride Ponding Test:
This test helps in determining the depth to which chloride ions can ingress into the concrete over a period of time under standard conditions. It is used to assess concrete for its resistance to chloride attack and thus protection of the reinforcement from corrosion.
Cube Compressive Strength:
The cube test is most commonly used for determining the value of compressive strength that can be used to assess whether the batch that the concrete cube represents, meets the required compressive strength or not. A cube of concrete in the cast is cured for the appropriate time and is then compressed between two parallel faces.
Test Method: IS: 456, IS: 15658-2006, IS: 516-1959
Depth of Carbonation:
Carbon dioxide penetrates the concrete pores. This penetration is faster when concrete is more porous. It can then react with cement to form carbonates. This reaction decreases the concrete pH so, carbonation starts on the concrete surface and concerns some thickness (called carbonation depth) of the material. Carbonation is a typical form of deterioration. Enough carbonation gives concrete the immediate positive effects of increased, compressive strength, modulus of elasticity, surface hardness, resistance to frost, sulphate attack, internal stresses and the ultimate reduction of the structure’s capacity.
Drying Shrinkage/ Wetting Expansion Test:
A common saying is that there are two guarantees with concrete. One, it will get hard and two, it will not crack. Cracking is one of the major causes of complaints in this industry. Cracking can be the result of one or a combination of factors such as drying shrinkage, thermal contraction, restraint (external or internal) to shortening, subgrade settlement, and applied loads. Values of wetting expansion and drying shrinkage of concrete are often useful during the time of mix design trials to ensure that concrete will exhibit values that are within normal ranges.
Test Method: IS: 1199-1959
Flexural Strength Test:
Flexural Strength is the ability of a beam or slab to resist failure in bending. It is measured by loading un-reinforced 6×6 inch concrete beams with a span three times the depth (usually 18 in.).
Test Method: IS: 516-1959, ASTMC 494-2010
Concrete durability is related to porosity, which determines the intensity of interactions of the material with aggressive agents. The pores and capillaries inside the structure facilitate the destructive processes, that generally begins at the surface. Generally, concrete of a low porosity can afford better protection than the concrete of high porosity. Porosity can be measured by vacuum saturation of a concrete specimen, measuring its weight gain and expressing this as a percentage of the mass of the sample.
Measuring the Sulphate content of concrete is used to check that the sulphate levels are low enough to avoid any later problems with deterioration of the concrete. This test can be used at concrete mix design stage to ensure low sulphate levels have been achieved, or on older concrete structures to measure the level of ingress of sulphate. Tests can be conducted through multiple types of chemical means.
Test Method: BS: 812(P-118)
Water Absorption Test:
This test helps in determining the rate of absorption of water in cement concrete by measuring the increase in the mass of a specimen resulting from absorption of water during the time when one surface of the specimen is exposed to water. The exposed surface of the specimen is immersed in water and water ingress of unsaturated concrete dominated by capillary suction during initial contact with water.
Test Method: ASTM C 1084
Water Penetration Test:
Water penetration is used to measure the surface hardness and the strength of layers near-surface of the concrete. Water penetration causes the concrete reinforcement to rust and expands which in turn creates stress on the surrounding concrete.
Test Method: ASTM C 1084
Pile Integrity Test (PIT):
This test is done to measure Pile length, depth to anomalies, Pile head stiffness, Pile shaft mobility – which is dependent on pile section and concrete properties.
Concrete Admixture is a chloride free, high-range, water-reducing admixture. It disperses the fine particles in the concrete, enabling water content in the concrete to perform more efficiently and improve the consistency of concrete.
Test Method: IS: 9103 / 1999