Influence of sand grading,fines content and clay content on properties of sand-gypsum mortar

The paper summarizes a series of tests carried out on gypsumsand mixes—made of crushed dolomitic stone sand and retarded hemihydrate—seeking answers to the following questions:

1. Does the sand grading affect mortar properties?
2. How do the fines (fraction passing No. 100 sieve) affect mortar properties?
3. How does the clay content influence the properties of mortars?

Evaluation criteria for the hardened mortars were: flexural and compressive strength, hardness and linear change.