EVALUATION OF D-CRACKING FAILURE OF CONCRETE PAVEMENTS CONTAINING CARBONATE AGGREGATES

Deterioration of concrete pavements due to D-cracking has been a major, long term problem for concrete composed of carbonate coarse aggregates. Beam freeze thaw testing (ASTM 666) is a proven method for predicting concrete durability, but the method involves 350 cycles of testing and a 3.5 month time span. Testing of the unconfined aggregates is less time consuming, but typically yields less reliable results. Test substitutes for ASTM 666 have been proposed which merit further consideration (Desta and West, Proc. Highway Geology Symposium, 2015). Presented here is another approach. A comparison of unconfined aggregate testing procedures with beam freeze thaw results to determine if some combination of these tests can prove useful in discerning the unacceptable aggregate sources. It is well-established that the limits set for other types of concrete deterioration should be reduced when applied to the D- cracking problem and that aspect is examined in this discussion. Standard tests considered are: 1. bulk specific gravity and absorption; 2.brine freeze thaw (ASSHTO T103); 3. sodium sulfate soundness (T104); 4. acid insoluble residue; and 5. petrography. Results from the above test procedures are compared to those of beam freeze thaw testing of concrete based on 18 sources of carbonate aggregates from Indiana (Desta, et al., 2015).