Category: Concrete

After fixing, the desired proportion of quantity of required ingredients, viz., cement, coarse-aggregate, fine-aggregate, cement and sand, has to be measured out in batches for mixing. This process of measuring out ingredients is called batching. Batching may be done by weight or by volume. Volume batching is inferior to weight batching as using the former…

After fixing, the desired proportion of quantity of required ingredients, viz., cement, coarse-aggregate, fine-aggregate, cement and sand, has to be measured out in batches for mixing. This process of measuring out ingredients is called batching. Batching may be done by weight or by volume. Volume batching is inferior to weight batching as using the former…

Selection of the proper quantity of cement, coarse aggregate, sand and water to obtain the desired quality is known as proportioning of concrete. Concrete is formed by successive filling of voids in aggregate by sand, the voids in sand by cement and voids in cement by water and undergoing a chemical reaction. The concrete formed…

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:

Bureau of Indian Standards (BIS) has recommended a Mix Design Concept mainly based on the research works performed in national laboratories. This method can be applied for both medium-strength and high-strength concretes. The step-by-step approach of the BIS mix design is given below. Table 8.10 Adjustment of value in water content and sand percentage for other…

This method has been used since 1944 and has undergone several revisions continuously. It has developed an identical procedure for angular or rounded aggregates, regular or light-weight aggregates and air-entrained or non-air-entrained concretes. The ACI mix design is based on certain factors which are established by field experience on large works. The factors are as…

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…

The discussion so far has been centered on the modification of the properties of concrete using admixtures. Other chemicals that are used to enhance the performance are discussed in this section. Such chemicals are referred to as construction chemicals or building chemicals. Concrete-curing Compounds The measure adopted to prevent the loss of water from the…

Admixture and construction chemicals are chemicals added to the ingredients of concrete to obtain the desired strength and durability. 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 added…