Author: haroonkhan

Water being light in weight moves upward in concrete, which leads to bleeding. This water evaporates to make the top surface porous having very little abrasion resistance. Masons often float the concrete when the bleeding water is still standing on the surface. Too much of working on the exposed surface leads to pressing the coarse…

Plastic concrete settles when vibrated. There will be no cracks if the concrete settles uniformly. Some cracks are bound to occur if there is any obstruction to uniform settlement due to reinforcement or larger pieces of aggregates. Such cracks are called settlement cracks. Such cracks are formed generally in deep beams.

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 than the migration of water from the interior to the surface. This creates a moisture gradient which results…

Factors that contribute to the formation of cracks in cement concrete are discussed below.

The following tests are commonly employed to measure workability of fresh concrete: Slump Test It is the most commonly used method of measuring consistency of concrete. This test can be conducted in the field or in a laboratory. However, this test is not suitable for very wet or very dry concrete. The apparatus for conducting…

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.

Applied finish is the exterior application of rendering made on concrete structures. In this case the concrete surface is finished and kept wet after which mortar (1:3) is applied. The desired finish is then given to the mortar. Sometimes the rendering applied on a wall is pressed with a sponge. On repeating this process, the…

This is a commonly used method of surface finishing. It is important for a residential floor to be smooth. To obtain a smooth finish, first the proportioning of mix should be appropriate. The finishing of surface should be at the same rate as that of placing of concrete. Attention must be paid to the extent…

Concrete maintains the shape of formwork, i.e., centering work. Thus, keeping the required shape through formwork, viz., undulated fashionable shapes, V-shaped finishes, plain surfaces, etc., any pleasing surface can be obtained. The imaginative ideas of architects may be implemented by a careful formation of concrete surface. A properly made out formwork can give a very…

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…