What are the basic requirements to be satisfied by any concrete to be used for normal buildings (G+5 storey or small). I mean in general sense, what should be the slump value, what should the minimum compressive strength and what should be the min. setting time?
Sir thanks for the ans. but I was asking in a general point of view, that means the minimum requirements. Mohannad H. Al-Sherrawi
Concrete should have graded aggregates with proper properties like crushing and impact test results conforming to specifications. Proper water cement ratio so that required strength is achieved and proper workability to transport and place it.
Which means a proper mix design must be ensured to meet the specific requirements.
You may design concrete for M20 grade with 50-75 mm slump. Higher grade of concrete can reduce the column sizes and functional area can be increased if number of columns are more. Workability in terms of slump value also depends on what type of methods are used for laying and compaction of concrete.
Concrete shall be workable (during concreting), durable and impermeable (service condition), in order to be workable, durable and impermeable, the concrete needs to be designed (design mix) for the requirement.
Basic properties of normal concrete for smooth working are as bellow.
1.Grade of concrete should be equal to the structural requirement or as per given in drawing.
2.Concrete mix should be cohesive & workable ,
3.Concrete mix design should be done for maximum retention time and it should placed within design time at site
4.For pumping of concrete at 6th floor you have to check visually segregation and bleeding in concrete , if found in concrete then do not use that concrete
5.At placement of point concrete should be cohesive , without segregation and bleeding , I do not suggest for slump checking, go with flow test value for normal concrete is -400 - 550 mm.
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