Influence of concrete composition on anchorage bond behavior of prestressing reinforcement: Fid-Bau Portal

Influence of concrete composition on anchorage bond behavior of prestressing reinforcement

Martí-Vargas, J.R. / García-Taengua, E. / Serna, P.

Highlights • Bond behavior of strands is analyzed by measuring forces at transfer and at loading. • A parameter including strand end slip is used in determining anchorage length. • Concrete composition and strength affect the anchorage length of prestressing strands. • There is a potential bond capacity by strand slippage within the anchorage length. • The ACI 318-11 provisions for anchorage length result conservative.

Abstract An experimental research addressing the effects of concrete composition and strength on anchorage bond behavior of prestressing reinforcement is presented to clarify the effect of material properties that have appeared contradictory in previous literature. Bond stresses and anchorage lengths have been obtained in twelve concrete mixes made up of different cement contents (C) – 350 to 500kg/m³ – and water/cement (w/c) ratios – 0.3 to 0.5 – with compressive strength at 24h ranging from 24 to 55MPa. A testing technique based on measuring the prestressing force in specimens with different embedment lengths has been used. The results show that anchorage length increases when w/c increases, more significantly when C is higher; the effect of C reveals different trends based on w/c. The obtained anchorage bond stresses are greater for higher concrete compressive strength, and their average ratio of 1.45 with respect to transmission bond stresses implies a potential bond capacity.