Useful Processes For RCC Slab Casting
Utilized Materials and Machinery
Chute and CI Pipes
Possibility of the work
• Marking the slab
• Positioning the reinforcement
• Form work in support of slab
• Positioning the concrete
It should adhere to BBS and be produced in accordance with sanctioned drawing. Once shuttering is finished, the R/F shifting and binding must be created. R/F binding shall carry on as formwork and shuttering work should continue.
Before commencement of concrete work, the construction joint shall be predetermined and settled. Suppose there are two construction joints for main building as per your plan, if any significant break down of the Batching plant occurs, the supplementary Construction joint may be abandoned. The position of the construction joint should have been at the one-third distance. Construction joint are straight and should contain profile of ‘L’shape in order that subsequent layer of concrete is mixed properly with the layer placed earlier.
Formation of construction joint will consist of roughening, eliminating all laitance abided by the joint and use of thick slurry prior to develop the new concrete.
Production and placement of concrete
• Before commencing the concrete work, there should be ample stock of material. Be confirmed from the stores/purchase dept that concreting is not obstructed due to scarcity of materials.
• All plant and machinery should be examined on a regular basis to ensure that they are in working conditions.
• Concrete of grade M-25 must be developed from the batching plant and directly pumped to the location of concrete placing over the pipeline. The order of pouring should start from grid A towards construction joint. If the grade of concrete for column is M-40 and adjacent concrete is M-25, adequate offset around column shall be casted with M-40.The offset dimensions are furnished by PMC.
• Appropriate walkways/platforms are set with the intention that the supports of the pipeline and manpower are not directly depended on reinforcement.
• There should enough carpenters together with supervisor to check the behavior of supports below the slab throughout the casting. Extra Props should be reserved below slab to offer extra supports to resist any failure of supports.
The curing is commenced right away once the thumb set of the concrete is arranged. Provide a cover with hessian clothe /plastic to the set concrete to decrease moisture evaporation out of the concrete throughout hardening and thus get rid of shrinkage crazy cracks. These cracks are hereditary property of the concrete which may occur throughout casting of flat surfaces.
Final curing should be performed by spraying and stacking water for at least 7 days.