soundness

Presence of excess quantities of free lime and magnesia in the cement , causes unsoundness in the cement . These substances slake very slowly and cause volumetric expansion in already set concrete , which may result in the distegration of the concrete . Soundness of the cement is measured either by Lechateliar method or by Autoclave method . All the sound cements should not exhibit expansion of more than 10mm by Le-chatelier  method and 0.5 % by Autoclave method . Le-chatelier method of test is done as given is done as given is IS : 4031 -1968 .