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Chemical Admixtures

  Chemical Admixtures Chemical admixtures are the ingredients in concrete other than Portland cement, water, and aggregate that are added to the mix immediately before or during mixing. Producers use admixtures primarily to reduce the cost of concrete construction; to modify the properties of hardened concrete; to ensure the quality of concrete during mixing, transporting, placing, and curing; and to overcome certain emergencies during concrete operations.  Successful use of admixtures depends on the use of appropriate methods of batching and concreting. Most admixtures are supplied in ready-to-use liquid form and are added to the concrete at the plant or at the jobsite. Certain admixtures, such as pigments, expansive agents, and pumping aids are used only in extremely small amounts and are usually batched by hand from premeasured containers.  The effectiveness of an admixture depends on several factors including: type and amount of cement, water content, mixing time, slump, and temper
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4 Types of Cracks in Concrete Columns and their Causes

  Four types of cracks developed in reinforced concrete column are diagonal cracks, horizontal cracks, splitting cracks, corrosion cracks. The causes of cracks in columns can be incorrect design, faulty construction or overloading, corrosion of reinforcement, isolated settlement of foundations, creep and shrinkage. Cracking in reinforced concrete column is a serious problem and it may lead to the loss of strength, stability, durability, and detrimentally influence aesthetics. Therefore, it is required to investigate different types of cracks that may initiate in columns in order to consider suitable means to restrict them. Types of Cracks in Concrete Columns 1. Diagonal Cracks Diagonal cracks in reinforced concrete columns develops and encompass the entire face of column anywhere along its height. The main cause of diagonal cracks in concrete columns is inadequate load carrying capacity of the columns; insufficient cross-section and inadequate reinforcement steel. Diagonal Crac
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Non-destructive tests of concrete

  Non-destructive tests of concrete is a method to obtain the compressive strength and other properties of concrete from the existing structures. This test provides immediate results and actual strength and properties of concrete structure. The standard method of evaluating the quality of concrete in buildings or structures is to test specimens cast simultaneously for compressive, flexural and tensile strengths. The main disadvantages are that results are not obtained immediately; that concrete in specimens may differ from that in the actual structure as a result of different curing and compaction conditions; and that strength properties of a concrete specimen depend on its size and shape. Although there can be no direct measurement of the strength properties of structural concrete for the simple reason that strength determination involves destructive stresses, several non- destructive methods of assessment have been developed. These depend on the fact that certain physical pro
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About Ready Mixed Concrete

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  About Ready Mixed Concrete Learn how the natural ingredients of concrete combine to form a remarkably strong, durable and economical building material that has been benefiting mankind for millennia.   Concrete Basics In its simplest form, concrete is a mixture of paste and aggregates (sand & rock). The paste, composed of cement and water, coats the surface of the fine (sand) and coarse aggregates (rocks) and binds them together into a rock-like mass known as concrete. Within this process lies the key to a remarkable trait of concrete: it’s plastic and can be molded or formed into any shape when newly mixed, strong and durable when hardened. These qualities explain why one material, concrete, can build skyscrapers, bridges, sidewalks, and  superhighways, houses and dams. The key to achieving a strong, durable concrete rests on the careful proportioning and mixing of the ingredients. A concrete mixture that does not have enough paste to fill all the voids between the aggr
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