Production and Engineering Properties of Concrete Used in Precast Prestressed I-Beams for the State of Indiana. Volume 1. Executive Summary

摘要

The report describes engineering properties and current production procedures of concrete for precast prestressed I-beams in the state of Indiana. Current production techniques used in precast plants to obtain higher strength concrete are evaluated. The results of the study indicate that proper quality control and the use of admixtures have facilitated the production of concrete with 28 day compressive strength exceeding 7000 psi. A survey of 5 precast plants in Indiana and Kentucky indicated that an increase in the 28 day compressive strength requirement could be specified without major changes or additional cost to the product. Data from a year around study with field cured specimens indicated that the current empirically derived expressions to determine modulus of elasticity and tensile strength could be used in concretes with compressive strength up to 9000 psi.