Laboratory Investigation of Lightweight Concrete Properties

About the report:

Lightweight concrete (LWC), with its reduced weight and improved durability, enables longer spans, fewer piers, and longevity for bridge structures.  The current emphasis on upgrading structures makes LWC highly desirable as a construction material since superstructures with wider shoulders or more lanes can be upgraded without major work on the substructure. 

The purpose of this study was to evaluate the density (unit weight), splitting tensile strength, and elastic modulus of LWC mixtures under different curing conditions to achieve a better understanding of the LWC properties that are essential for long-lasting and cost-effective structures.  Further, the study examined the correlation between the results of the rapid chloride permeability test and the surface resistance test using the Wenner probe to investigate whether the latter could be used to predict the permeability of LWC mixtures, as it is faster and more convenient.  The scope of the study was limited to LWC mixtures having different lightweight aggregates prepared and tested in the laboratory.

The results indicated that measured densities are different than those calculated from batch weights; curing conditions affect the splitting tensile strength and elastic modulus values; and the correlation between the results of the rapid chloride permeability test and the surface resistivity test for a given lightweight aggregate was good. 

The study recommends that fresh concrete densities be used in designing for dead load computations of LWC structures; that the curing condition be stated for the hardened concrete properties; and that the surface resistivity test be permitted for screening or acceptance of LWC specimens for permeability after the test is standardized by the American Association of State Highway and Transportation Officials.

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