Following are the effects on concrete due to segregation. Effects on Concrete A segregated concrete is very weak in strength Due to segregation after placing, the concrete in the lower part of a pour of any significant depth can be stronger than that in the upper part. Segregated concrete does not give a homogeneous mass … Read more
Segregation usually implies separation of: (a) coarse aggregate from fine aggregate, (b) paste from coarse aggregate, or water from the mix and the ingredients of the fresh concrete no longer remain uniformly distributed. The points given below are the primary causes of segregation of concrete in field. Causes of Segregation on Site Poorly graded aggregate … Read more
What is Segregation? Wordweb dictionary defines the term “segregation” as – Separation or isolation of one thing from another and place in a group apart from others. In concrete technology, segregation can be of two types. Firstly the coarse aggregate may separate from the main mass of concrete in its plastic state. Secondly, the grout … Read more
Factors Affecting Workability of Concrete A concrete is said to be workable if it is easily transported, placed, compacted and finished without any segregation. Workability is a property of freshly mixed concrete, and a concrete is a mixture of cement, aggregate, water & admixture. Due to this all the properties of concrete, whether in fresh … Read more
Before knowing the term workability let us look at some of the definitions given by scientists and researchers. Definitions of Workability of Concrete According to Granville “it is that property of the concrete which determines the amount of useful internal work necessary to produce full compaction.” Powers defined it as “that property of plastic concrete … Read more
Mix design is a process of selecting suitable ingredients and determining their relative proportions with the objective of producing concrete of having certain minimum workability, strength and durability as economically as possible. Concrete A mix design can be designed in two ways as explained below Nominal Mix Design Nominal Mix It is used for relatively … Read more
What is Gap Graded Aggregate? Generally we use well graded aggregate or continuous graded aggregate, which means representation of all the standard particle sizes in certain proportion. Assumption made in well gradation is that voids created by the higher size of aggregate will be filled-up by immediate next lower size of aggregate and again some … Read more
The volume increase of fine aggregate due to presence of moisture content is known as bulking. Fine sand bulks more as compared to coarse sand. Extremely fine sand particularly the manufactured fine aggregate bulks as much as about 40%. Note: Fine aggregate do not show any bulking when it is absolutely dry or completely saturated. … Read more
Objective The tests are required to determine the strength of concrete and therefore its suitability for the job. Reference Standards IS : 516-1959 – Methods of tests for strength of concrete. Equipment & Apparatus Compression testing machine (2000 KN) Curing tank/Accelerated curing tank Balance (0-10 Kg) Procedure Representative samples of concrete shall be taken and … Read more
Objective Normally, the strength of concrete is found out after 7 days and 28 days. For some construction activities, it may be too late and need to know the strength earlier. Reference Standards IS: 9013-1978-Method of making, curing and determining compressive strength of accelerated cured concrete test specimen. Equipment & Apparatus Accelerated curing tank Compression Testing Machine … Read more
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