Limestone Sand Subbase
Apr 29, 2021
19
| STATEMENT OF PROBLEM: Even after compaction of limestone sand, the concrete trucks would create ruts while crossing the grade. Extra grading would be needed as concrete was being placed to reduce this rutting. COURSE OF ACTION: The limestone sand was replaced with crushed limestone where feasible to provide a more suitable sub-base to drive heavy equipment on. For instances where the limestone sand was still used, the area would be graded during the process of placing concrete to reduce rutting as much as possible. LESSON FOR FUTURE PROJECTS: After discussing this issue with others who have used 21AA limestone sand as a sub-base for concrete, we learned that if the sand has a couple of days to "set" after it has been graded and compacted, it becomes a much more suitable driving surface for heavy equipment. We would still recommend switching to crushed limestone instead of sand if the project is on a tight schedule where there is not suitable time between grading and placing concrete for the sand to set. When a solid sub base is needed for heavy construction traffic/manueverability, should stick with 21AA crushed limestone or crushed concrete instead of the limestone sand. |
