Category: CONCRETE MASONRY

 Ingredients of Lime Concrete Lime concrete is made of lime, fine aggregate and coarse aggregate and mixed in suitable proportions in addition to water. Hydraulic lime is generally used as a binding material, sand, surkhi and cinder are used as fine aggregates, and broken bricks or broken stones are used as coarse aggregates. 8.14.2 Properties of Lime…

Non-destructive testing is done on hardened concrete. In non-destructive testing methods, some properties of concrete are used to estimate strength, durability, elastic parameters, crack depth, micro-cracks and progressive deterioration of concrete. Such properties of concrete are hardness, resistance to penetration of projectiles, rebound number, resonant frequency, ability to allow ultrasonic pulse velocity, ability to scatter…

Quality control implies that the assigned work is done according to the specifications agreed in the contract. Major civil engineering works such as multistoreyed buildings, dams, harbours, etc., have to be constructed with utmost care as they have to last and be used for decades. Specifications of work should be framed based on cost or…

Factors that contribute to the formation of cracks in cement concrete are discussed below. 8.11.1 Plastic Shrinkage Cracks Evaporation of water from fresh concrete is due to the absorption by formwork and during the hydration process. The surface of concrete dries up when the loss of water from the surface of the concrete is faster…

Testing of fresh and hardened concrete is important in concrete construction. Tests are conducted on fresh concrete to check the workability of concrete, and on hardened concrete to determine the strength, creep effects, durability, etc. 8.10.1 Testing of Fresh Concrete The following tests are commonly employed to measure workability of fresh concrete: 1. Slump Test…

Finishing is the last stage in concrete construction. After casting of a concrete, the concrete does not offer a pleasant architectural appearance. In some cases like beams, finishing may not be needed. For a residential building, airport or road pavement and culvert and bridges, finishing is a must. Now-a-days, the centering materials are so made…

While manufacturing concrete, it should be ensured that every batch of concrete has the same proportions. This is a mandatory requirement so as to satisfy two aspects, viz., same workability and uniform strength. In the manufacturing of concrete the following steps are followed: 8.8.1 Proportioning of Concrete Selection of the proper quantity of cement, coarse…

Mix design of concrete is the process of selecting the required ingredients of concrete and finding their relative proportions with the aim of producing an economical concrete of certain strength and durability. It has been discussed earlier that concrete is based on two phases, viz., aggregate phase and paste phase. Workability of the concrete depends…

During 1976 there was only one type of cement available. Later OPC had been graded and the gain in strength after 28 days had been based on the grade and type of cement. The design was based on 28 days’ characteristic strength of concrete unless there was evidence to justify a higher strength for a…

Admixture and construction chemicals are chemicals added to the ingredients of concrete to obtain the desired strength and durability. 8.5.1 Admixtures Of late concrete is used for varied purposes and is made suitable for different occasions and environments. Ordinary concrete is not as versatile and does not suit all purposes. Thus, admixtures and chemicals are…