Check Tests of Materials

Without follow-up field control, all the statistical theory involved in mixed proportioning becomes an academic exercise.
The complete description of initial proportions should include: cement analysis and source; specific gravity, absorption, proportions of each standard sieve size;
fineness modulus; and organic tests for fine and coarse aggregates used, as well as their weights and maximum nominal sizes.
If the source of any aggregate is changed, new trial batches should be made. A cement analysis should be obtained for each new shipment of cement.
The aggregate gradings and organic content should be checked at least daily, or for each 150 yd3. The moisture content (or slump) should be checked continuously for all aggregates, and suitable adjustments should be made in batch weights. When the limits of ASTM C33 or C330 for grading or organic content are exceeded, proper materials should be secured and new mix proportions developed, or until these measurements can be effected, concrete production may continue on an emergency basis but with a penalty of additional cement.

Scroll to Top