Semester

Fall

Date of Graduation

2002

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Julio F. Davalos

Committee Co-Chair

Indrajit Ray.

Abstract

Protective concrete deck overlays have been successfully used by WVDOH in a number of old and new concrete bridge decks to extend their service life, but in several cases delamination and failures have been observed. A comprehensive study has been recently defined to investigate overlays performance and delamination, culminating eventually in the development of specifications in collaboration with WVDOH and the Contractors and Building Supplies Associations of WV.;The present study is an exploratory research concerned with evaluations of four types of overlays for bridge deck applications, and include: latex modified concrete (LMC), microsilica modified concrete (MMC), microsilica modified concrete with fly ash (MMC-FA) and polypropylene fiber-reinforced concrete (FRC). The laboratory mixtures were developed using local aggregates, Type-I cement and commercial admixtures and fibers. Mixtures were evaluated by several tests in both fresh and hardened states, including compressive, tensile, and flexural strengths, shrinkage and chloride-ion permeability. To evaluate the performance of overlay-substrate interface behavior, a new compression loading block shear apparatus was developed, and for each type of overlay, double wedge-type bi-layer specimens of overlay-substrate were tested for two different substrate surface preparation conditions: Mechanical abrasion and chemical etching.;The results show that FRC had the highest compressive and split tensile strengths, and MMC and MMC-FA had very low chloride permeability values, while LMC exhibited extremely high interface bond strength. The surface preparation differences indicated that mechanical abrasion performed marginally better than chemical etching for most of the bi-layer specimens. This study provides the bases for streamlining the large-scale efforts to be undertaken on development and characterization of overlays for West Virginia.

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