Subgrades and Subbases for Slabs| Concrete Construction ...
Nov 22, 2017· 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 laterage cracks and poorer joint performance." Here are the reasons not to use a sand layer: · Difficult to maintain a flat, level sand surface during concrete placement · Difficult to ...