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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Concrete Q&A: Concrete Cover for Unbonded Tendons
Author(s): Post-Tensioning Institute (PTI) staff
Publication: Concrete International
Appears on pages(s): 72
Abstract:Q.I have a question regarding tolerances for concrete cover for unbonded tendons in post-tensioned concrete. Section 184.108.40.206.f of ACI 301-101 states: "Unless otherwise specified, concrete cover for the tendon end from the exterior edge of the concrete shall not be less than 3/4 in. for nonaggressive environments and 1 in. to the encapsulating device for aggressive environments." Section 220.127.116.11 of ACI 301-10 also states the following regarding tendon tolerances: "Place tendons and anchorages within the tolerances of ACI 117 for reinforcement placement, distance between reinforcement, and concrete cover." However, ACI 117-102 does not appear to include any tolerances for the concrete cover for tendon ends in unbonded post-tensioning systems. Are there any such tolerances? Is there a separate concrete cover requirement for unbonded post-tensioned tendon ends that are angled at 45 degrees to the horizontal? I’m afraid that the stressing pocket might hold water if the building cladding allows moisture to penetrate to the slab edge.
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