Disposal of limestone screenings, or limestone fines, creates problems for many quarry operations. Much of the fines is either stockpiled or deposited back into the quarry pit. A laboratory study and pilot project was conducted to determine if limestone screenings could be stabilized and usedas a structural layer in road construction. This project set forth the following objectives: determine from laboratory experiments if limestone screenings could be stabilized and used as a structural layer in road construction and evaluate the effectiveness of stabilized limestone screenings as a structural layer in road construction through performance monitoring.Compaction, unconfined compression, freezing and thawing durability, and wet-dry durability tests were performed to determine if limestone screenings could be stabilized and used as a structural layer in road construction. Falling Weight Deflectometer (FWD) tests were used to compare stiffness differences, and temperature data was used to determine the number of freezing and thawing cycles each test section underwent. Laboratory compactionand unconfined compression test results confirm that limestone screeningscan be stabilized for use as a structural layer. Freezing and thawing and wet-dry durability test results show that cement kiln dust (CKD) is not an acceptable stabilizer due to poor durability performance. Class C fly ash (FA) and CKD mixtures were determined to be acceptable. Test section one (30% CKD) most likely failed due to freeze-thaw action. Visual observations show good performance of test section two (15% FA and 15% CKD) and the two control sections with no rutting or pothole formation.
Samenvatting