The various process involved in any concreting operation involves the following stages. Mixing Transporting Placing Consolidating As concrete passes from one stage to another, it starts to lose its plasticity characteristics. If after placing it is not disturbed for a longer time period, then it starts to become stiffening. As a result concrete changes its … Read more
Objective Determination of initial and final setting time of concrete as per IS-8142-1976. Apparatus • Non absorptive metal container having minimum lateral dimension of 150 mm and minimum depth of 150 mm. • Penetration resistance apparatus having a pressure gauge of capacity 700 to 900 N. Removable needles of 645, 323, 161, 65, 32 & … Read more
There are different methods of measuring the workability of fresh concrete. Each of them measures a particular aspect of it and there is no unique test which measures workability of concrete in its totality. The three most commonly used method for testing workability of concrete are Slump test Vee-bee test Compacting factor test. The table … Read more
Objective To determine the workability of freshly mixed concrete by using of Vee – Bee consistometer apparatus. Scope and Significance The workability of fresh concrete is a composite property, which includes the diverse requirements of stability, mobility, compactability, placeability and finishability. There are different methods for measuring the workability. Each of them measures only a … 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
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
Objective For determination of relative quantity of mixing water that will bleed from a sample of freshly mixed concrete. Reference Standard IS : 9103-1999 – Method of sampling and analysis of concrete. Equipment & Apparatus Cylindrical measure Tamping Bar Pipette Graduated Jar Procedure The container is filled with concrete up to a height of 250±3 … Read more
Objective For determination of consistency of concrete where the nominal maximum size of aggregate does not exceed 38 mm using flow table apparatus. Reference Standard IS : 1199 – 1959 – Method of sampling and analysis of concrete. Equipment & Apparatus Flow table Procedure Before commencing test, the table top and inside of the mould … Read more
Objective For determination of consistency of concrete where the nominal maximum size of aggregate does not exceed 38 mm using compacting factor test apparatus. Reference Standards IS: 1199 – 1959 – Method of sampling and analysis of concrete. Equipment & Apparatus Compacting factor apparatus. Procedure The sample of concrete to be tested is placed … Read more
Object For determination of consistency of concrete where the nominal maximum size of aggregate does not exceed 38 mm using slump test apparatus. Reference Standards IS : 1199 – 1959 – Method of sampling and analysis of concrete. Equipment & Apparatus Slump cone Tamping rod Procedure The internal surface of the mould is thoroughly cleaned … Read more