James R. Lundy

Use and Effects of Studded Tires on Oregon Pavements

The use and effects of studded tires in Oregon are investigated, updating a 1974 report. Studded-tire use was surveyed, rut measurements collected, studded-tire traffic estimated, and pavement wear and damage analyzed. Studded-tire use in Oregon varies geographically. Half of the vehicles equipped with studs use them on all wheels, representing a significant change from 1974 practices. More than 23 percent of vehicles used studded tires in 1994. Studded-tire pavement wear coefficients were calculated and found to be half those reported previously. The coefficients for rigid and flexible pavements are 0.20 mm (0.008 in.) and 0.86 mm (0.034 in.), respectively, per 100,000 studded tire passes. Studded-tire wear will shorten pavement life on high-volume routes in Oregon. Asphalt pavements experiencing average daily traffic (ADT) volumes of 35,000 and 20 percent studded-tire use will reach the threshold rut in 7 years. Portland cement concrete (PCC) pavements experiencing 120, 000 ADT and 20 percent studded-ti...

ENVIRONMENTAL IMPACT OF CONSTRUCTION AND REPAIR MATERIALS ON SURFACE WATER AND GROUNDWATER: DETAILED EVALUATION OF WASTE-AMENDED HIGHWAY MATERIALS

An evaluation methodology was developed to help transportation agencies make prudent decisions about the reuse of waste materials and by-products in highway construction. The primary objective of this evaluation process was to assess the potential impact on surface water and groundwater of constituents released from these materials. Test materials included coal fly ash, bottom ash, blast furnace slags, scrap tires, foundry sand, and recycled asphalt pavement. Test materials were screened for potential aquatic impact in their raw form. Then they were amended with either asphalt or aggregate for detailed assessment, including leaching (batch and flat plate or column tests) and environmental removal, reduction, and retardation (soil sorption, volatilization, photolysis, and biodegradation) tests. Short-term bioassays were used to measure directly the potential aquatic impact of derived leachates as a supplement to chemical analyses. For most materials, amendment with asphalt or aggregate largely reduced or eliminated any impact on the aquatic organisms. Among environmental factors, soil sorption appeared to be the most effective contaminant-removal mechanism. All waste-amended asphalts and aggregates exhibited no measurable impact on target organisms after soil sorption. However, for materials such as pressure-treated wood and deck sealer (used as is), environmental tests showed little or no effect in reducing their aquatic impact.

Environmental Impact of Runoff from Highway Construction and Repair Materials: Project Overview

A study was conducted to identify the possible effects of highway construction and repair (C&R) materials on the quality of surface water and groundwater near the highway environment. The scope involved the development of a validated methodology to assess such effects in three phases. Phases 1 and 2 involved a survey of C&R materials, laboratory testing of the chemical and toxicological characteristics of a selected number of these materials, development and validation of a laboratory testing–based screening and evaluation methodology for highway C&R materials, and development of a mathematical model to simulate the fate and transport of water quality constituents, including toxicity, along surface and subsurface pathways in the highway environment. Phase 3 focused on 10 tasks designed to confirm the evaluation methodology, test various hypotheses of the model development, develop additional leaching and sorption data, compare ecotoxicological testing procedures developed during the project with standard Environmental Protection Agency procedures, refine laboratory protocols, enhance the model, and investigate the availability of field data for model testing.

NEW PROCEDURE FOR EVALUATING BOND STRENGTH OF CONCRETE REINFORCEMENT

The bond strength between concrete and reinforcement is critical to the performance of reinforced concrete structures, including continuously reinforced concrete pavements (CRCP). Unfortunately, a widely accepted test is not available for this critical property. Commonly used procedures apply the load to the reinforcing unit and the load is transferred from the unit to the concrete. Poissons effects are induced in the reinforcement and a reduction in cross section results. The ensuing failure is not generally representative of the stress transfer mode between concrete and reinforcement in most structures. The proposed procedure obviates the Poissons effects by applying the load directly to the concrete. Load is transferred to the steel in the vicinity of a preformed crack. Applicability of the procedure is demonstrated using a particular type of flat CRCP reinforcement; however, the procedure has been used on conventional steel and glass-fiber reinforced plastic reinforcement with equal success. The loading rate and instrumentation regime are adaptable to the needs of the researcher. Reinforced portland cement concrete specimens of various strengths were tested to evaluate the procedure and the reinforcement itself. The K-value was found to be satisfactory and comparable to conventional steel rebars. Also the mobilization of yield resistance ratios for the flat units were comparable to conventional steel reinforcing units.