Sand Base For Concrete Slab

A typical pad has a 4 inch layer of gravel underneath and about 4 inches of concrete on top.

Sand base for concrete slab.

A typical concrete mix contains 60 to 80 percent sand and gravel also known as an aggregate this aggregate compound is more than filler. Almost 20 years ago concrete construction investigated the effect of using a layer of loose uncompacted sand directly beneath a concrete slab and concluded that this practice contributed to more later age cracks and poorer joint performance here are the reasons not to use a sand layer. When building a landing for deck stairs typical codes require the pad to extend beyond the steps about 36 inches behind the steps about 12 inches and on the sides of the steps about 6 inches. The base course material according to aci 302 concrete floor and slab construction should be compactible easy to trim granular fill that will remain stable and support construction traffic aci 302 recommends material with 10 to 30 fines passing the no.

Laying a concrete shed base involves the same clearance and levelling of land as with a paving slab shed base. 100 sieve with no clay silt or organic materials. The amount of sand and gravel in a bag of concrete determines the mixture s strength and texture. From american concrete institute aci360r 10 guide to design of slabs on ground 4 5 design of slab support system 4 5 1 general after subgrade soils have been classified the general range of k values can be aproximated from fig 4 3.