If slump results from test show shear or collapsible slump, then it should be rejected, and the test should be repeated. Now, if at site RMC is used and slump results are not satisfactory, then we can manage the water-cement ratio by adding more cement content, which will increase strength. Also, we can use admixtures such as plasticizers or superplasticizer to maintain workability of concrete.

Arnold Shelton
Management consultant