Generally we specify workability of concrete in terms of its slump test value. But sometimes it is also specified by another test called compaction factor. The relation between slump and compaction factor is roughly as follows. Relation Between Slump & Compaction factor Workability Slump in mm Compaction factor Very stiff – 0.70 Stiff 0 to … Read more
Objective To measure flow value of concrete using flow table apparatus Equipment Flow table Slump cone shaped mould Wooden tamping bar Procedure Place the flow table on a leveled surface Clean the top of the table and inner surface of the mould using a damp cloth. Place the slump cone centrally on the table. … Read more
Determination of setting time of concrete helps a site engineer in guiding the following areas. Importance of Setting Time of Concrete Whether or not to use any plasticizer To find out effectiveness of set controlling admixture Regulating maximum time of mixing transit, placing and compacting Whether or not to provide protection against adverse weather condition … Read more
The setting time of concrete depends upon following factors, such as Water-cement ratio Temperature condition Type of cement used Use of mineral admixture Use of chemical admixture (such as plasticizer) Other factors which may affect the setting time of concrete includes Absorption of mixing water by aggregates Grinding of aggregates in the mixer Of all … Read more
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
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
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
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
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