Tension Testing of Grouted Strand Anchorages

Cement grout encasement is the most common means of providing corrosion protection for strand anchorages for earth retention applications in the United States. The grout surrounds the strand and wedges and completely fills the wedge pockets. The effect of the grout on the performance of the anchorage is unknown and the ability to develop significant additional capacity above the lock-off load has not been verified by testing. A series of tests were conducted to determine if neat cement grouted strand anchorages can reliably develop load carrying capacity above the load at which they are locked off. The tests considered a range of lock-off loads, grout strengths, and surface condition of the wedges (clean or rusty). Baseline testing of ungrouted anchorages was also performed. Test results indicated that grout with compressive strength less than 38 MPa (5500 psi) did not adversely affect the ability of anchorages to develop load carrying capacity above the lock-off load, while very high strength grout with compressive strength greater than 81 MPa (12,000 psi) adversely affected performance. Rusty anchorages also performed poorly.