Shotcrete Acceptance Criteria
Final acceptance of shotcrete will be based on compressive strength results obtained from cores of test panels and shotcrete placement. In addition, all accepted shotcrete shall conform to the Execution and Material requirements set forth in this and other applicable sections, and initial and final set requirements.
Compressive strength acceptance of shotcrete
The average compressive strength of cores taken from the structure and test panels, representing a shift or ot more than 50 cubic meters of shotcrete (tested at 8 hours, 24 hours, 3 days, 7 days and 28 days) shall equal or exceed the minimum strength specified, with no individual core less than 85 percent of the required minimum compressive strength.
Test panel cores
For every shift or every 50 cubic meters of shotcrete placement, at lest one sample panel fabricated in accordance with ASTM C1140 shall be made. From each set of panels core specimens shall be taken as follows:
- Three core fore testing at 8 hours
- Three core fore testing at 24 hours
- Three core fore testing at 3 days
- Three core fore testing at 7 days
- Three core fore testing at 28 days
Core testing shall be made in accordance with ASTM C42, core samples shall be taken perpendicular to test panels in accordance with requirements of ASTM C1140.
Shotcrete structure cores
For every shift or every 50 cubic meters of shotcrete placement, at lest one sample panel fabricated in accordance with ASTM C1140 shall be made. From each set of panels core specimens shall be taken as follows:
- Three core fore testing at 8 hours
- Three core fore testing at 24 hours
- Three core fore testing at 3 days
- Three core fore testing at 7 days
- Three core fore testing at 28 days
Core testing shall be made in accordance with ASTM C42
Initial and Final Setting
During the course of the work the Engineer may at any time direct the Contractor to test materials for initial and final set for conformance with requirements. Such testing shall be in accordance with the specified testing method.
Further information on Shotcrete Curing and Protection
