International Concrete Abstracts Portal

Fracture behavior of polyester polymer concrete was investigated at room temperature using single edge notched beams loaded in four-point bending. To investigate the effect of particle size distribution on the fracture properties, polyester polymer concrete systems were formulated using both uniform Ottawa 20-30 sand and well graded blasting sand. The notch sensitivity of polyester polymer concrete systems was investigated by varying the notch-to-depth ratio up to 0.7. The results are analyzed to examine the applicability of fracture parameters such as critical stress intensity factor KIC and critical J-integral JIC, to characterize the fracture behavior of polyester polymer concrete. This concrete is a notch sensitive material, and if it contains well-graded aggregate, it has better fracture properties than the uniformly graded aggregate system.

A summary of the results of an experimental program to investigate the structural behavior of composite sandwich beams having polymer concrete (PC) on the top and bottom facings is presented. The possible application of PC as a facing material is of interest since it may provide an effective use for the material. A total of 18 different cross-sectional configurations were investigated. Polyester-based PC facings were used in conjunction with three separate core materials: sand-lightweight portland cement concrete, expanded polystyrene foam, and rigid polyurethane foam. Various combinations of core and facing thicknesses were used. Load-deflection responses, strain and stress distributions, modes of failure, and ultimate strengths of the beams were monitored. The experimental results were compared to sandwich beam theory and, in general, compared well. Overall, the results of the study suggest that the application of PC as a facing material holds high potential and warrants further attention.

Presents 6-year results of a study undertaken to evaluate multiple-layer polymer concrete overlays (MLPCO) over a 10-year period. The paper indicates that an overlay with low permeability and high skid resistance can be successfully installed by a contractor, state, or federal labor forces with minimum traffic disruption. The MLPCO evaluated were constructed with four polyester resins and silica sand, a polyester para-resin and silica sand, two flexible epoxies and basalt aggregate, and three EP5-LV epoxies and silica sand. A single-layer high molecular weight methacrylate overlay was also evaluated. With the exception of the overlay constructed with the polyester para-resin, the initial condition of the 20 overlays evaluated between 1981 and 1987 was good to excellent from the standpoint of permeability, skid resistance, and bond, although some overlays were better than others. Also, with the one exception, the overlays were in good-to-excellent condition after 1 year in service, but the permeability had increased and the bond strength and skid resistance had decreased significantly.

Results are presented from the preliminary phase of a laboratory test program conducted to identify and evaluate materials for converting hazardous geothermal residues to a nonhazardous and potentially usable form. Laboratory test results indicate that geothermal residues can be effectively incorporated as a fine aggregate into polymer concrete (PC) and portland cement mortar (PCM) composites. PC composites made using an emulsifiable polyester resin and a methyl methacrylate (MMA)-based monomer system exhibited compressive strengths varying between 3700 and 16,500 psi (25.5 and 113.8 MPa), depending upon the type of binder used and the moisture content of the residue. Waste extraction tests (WET) performed on ground samples of the composites indicate elemental levels of leachable heavy metals are below specified soluble threshold limit concentrations (STLC). PCM composites exhibited compressive strengths varying between 2875 and 5530 psi (19.8 and 38.1 MPa), depending upon the type, amount, and moisture content of the residue. WET analysis indicates elemental levels of leachable heavy metals are below specified STLC values for all but one of the PCM composites evaluated.

Polymer concrete (PC) has attracted significant interest in the past 15 years. It began primarily as a repair material for portland cement concrete, particularly bridges and pavements, and has now attracted considerable interest for other applications. A survey was conducted to determine the predicted needs and trends in the industry. The respondents, representing a wide range of backgrounds, indicated that precast products would have the greatest impact and, among precast products, utility components would lead the way. The greatest needs in the industry were deemed to be lower cost and improved monomers and resins. Many opinions were presented on the needed developments in materials properties. The author also presents his predictions on future trends in monomers and resins, aggregates, equipment, repair, precast products, and overlays. Future needs including improved training, public awareness, and research are discussed.