Title:
Transfer Length of Epoxy-Coated Prestressing Strand
Author(s):
Thomas E. Cousins, David W. Johnsone, and Paul Zia
Publication:
Materials Journal
Volume:
87
Issue:
3
Appears on pages(s):
193-203
Keywords:
bonding; building codes; corrosion resistance; epoxy resins; prestressed concrete; prestressing steels; pretensioning; protective coatings; stress transfer; Materials Research
DOI:
10.14359/2125
Date:
5/1/1990
Abstract:
To provide corrosion protection for seven-wire prestressing strand in prestressed concrete used in adverse environments, a strand manufacturer has developed and begun marketing an epoxy-coated strand. The seven-wire strand is coated with an epoxy and impregnated with a grit. The effect of the epoxy coating and grit on transfer length for three different sizes of prestressing strand was investigated. The transfer lengths of three different densities of grit were studied as well. Fifty-three specimens were cast to determine the transfer length of epoxy-coated and bare (uncoated) prestressing strand. The transfer length was determined by measuring concrete strains before and after release. Also studied were the effects of time on transfer length of epoxy-coated strand (referred to as transfer length creep), the relationship between end slip and transfer length of prestressing strand, and the effects of elevated temperatures on the transfer length of epoxy-coated strand. The experimental and analytical results from this research were compared to the results in the literature, provisions in the ACI Building Code (ACI 318-83), and previously proposed bond provisions.