Richard Lampo

The Utilization of Recycled Thermoplastic Composites for Civil and Military Load Bearing Applications

Long-term performance and extended service life are issues of vital importance to the Department of Defense (DoD). The DoD seeks alternative construction materials to replace more traditional materials, such as wood and steel, for heavily loaded infrastructure to combat this expensive corrosion and bio-degradation problem. Recently, two military bridge installations were completed, composed entirely of a reinforced thermoplastic composite lumber (RTCL) material that is capable of supporting the load of an M1 Abrams tank at approximately 64,410 kg (71 tons). The RTCL material selected for these applications is polypropylene (PP) coated fiberglass blended with high-density polyethylene (HDPE). Advantages of using RTCL include the following qualities: corrosion, insect, and rot resistance; no toxic chemical treatments required to increase service life; environmentally friendly; diversion of waste plastics from landfills; reduction of deforestation, green house gases, and global warming. RTCL has many advantages but does behave differently than traditional materials and certain properties must be addressed during the design stage. Both bridges are continually monitored, have performed well over the first year and a half, and are more cost-effective than any other construction material. Details of the material, design considerations, and construction are reviewed.

Bond strength between geotextiles and concrete

Abstract Geotextiles may be bonded to concrete by placing fresh concrete directly on a geotextile. A laboratory test program was developed to determine the influence of construction, characteristics of the geotextile, concrete, and load on the bond strength between concrete and geotextiles. Tests were conducted by casting 75 mm thick concrete blocks on top of a geotextile, allowing the concrete to cure, and then measuring the force required to peel the geotextile away from the concrete blocks. Results from over 120 tests on 16 different nonwoven and woven geotextiles indicate that bond strength is controlled significantly by details of the geotextile and construction details. The bond strength of nonwoven geotextiles was influenced significantly by the average distance between individual fibers within the geotextile, that is, the larger the distance between fibers, the more readily concrete can flow between fibers, anchor them in concrete, and thus provide bond. After placing the fresh concrete, vibration caused the bond strength to increase about 20% by allowing the cement to flow more readily around the fibers. Woven geotextiles bonded poorly with concrete unless geometric projections were provided. Woven geotextiles with projections bonded well with concrete but were sensitive to the direction in which load was applied.

Repair and Strengthening of Submerged Steel Piles Using GFRP Composites

AbstractSteel and concrete bridge structures that serve as the backbone of U.S. transportation and navigational infrastructure systems have been exhibiting moderate to severe deterioration within a few years of service. The focus of this paper is on the rehabilitation of water-submerged bridge steel piles using precured glass-fiber-reinforced polymer (GFRP) shells wrapped with water-curable GFRP prepreg fabrics. The GFRP shells were placed around the corroded steel piles of the East Lynn Lake Campground Bridge in Wayne County, West Virginia, and wrapped with GFRP fabrics. The space between GFRP shells and steel piles was filled with self-consolidating concrete to strengthen and protect the piles from further deterioration. Prior to field implementation, experiments were conducted on concrete cylinders embedded with steel I-sections that were encased by a polymeric shell and FRP wrap system to evaluate the load transfer mechanisms and increase in concrete strength as a result of confinement. To increase th...

Demonstration and validation of portable electrochemical impedance spectroscopy technology : final report on Project F11-AR08

The Department of Defense maintains many steel structures that are subject to corrosion. Coatings are a traditional first line of defense against corrosion, but a completely accurate assessment of coating condition cannot always be made by using only conventional visual inspection techniques because not all defects are visible. Alternatively, performing laboratory inspections can be difficult, time-consuming, costly, and may require testing specimens separately from the actual coated structure. This Office of the Secretary of Defense Corrosion Prevention and Control Program project sought to improve accuracy and lower costs (early detection of problems reduce future maintenance) by demonstrating and validating the capabilities of a portable electrochemical impedance spectroscopy (EIS) technology for evaluating coating health. A portable EIS system was demonstrated in a laboratory setting and at field locations on Fort Bragg, NC, and Fort Lewis, WA. The results showed the tested version of the portable EIS system has limited capabilities in comparison to traditional laboratory methods. Based on the results of the technology demonstration, the system needs further development before the anticipated benefits might be realized. Therefore, widespread implementation of the demonstrated system is not recommended at the current state, and the project’s return on investment is considered to be zero. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CERL TR-18-8 iii

Demonstration of a standard steel coating system modified with a vapor-phase corrosion inhibitor : final report on Project F12-AR14

This project demonstrated the capabilities of a vapor-phase corrosion inhibitor (VCI) as an additive into an epoxy primer coating for exterior hangar doors in a severely corrosive environment. Typically, protective coatings used on steel structures use zinc-loaded primers to provide corrosion protection to the substrate. As a more environmentally friendly option, a VCI-modified coating system has been used instead of a zinc-containing primer. The VCI migrates to the steel substrate to form a microscopically thin, corrosion-inhibiting film. The demonstrated coating system was also applied to test panels exposed to atmospheric weathering and to laboratory salt-fog exposure testing. The VCI-modified coatings were applied to abrasive-blasted substrates and to surfaces without the rust fully removed. Although the VCI-modified coating system showed promise in the test panel exposure results—especially panels with a lower grade of surface preparation—it was unable to protect the steel doors due to high levels of mechanical damage they incur during normal site operations. Based on the test panel results, further evaluation of the VCImodified coating system is considered necessary before making a positive recommendation for Army and DoD implementation. Due to the results of this demonstration, the project return on investment was zero. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CERL TR-18-29 iii

Full-Scale Testing of Thermoplastic Composite I-Beams for Bridges

United States. Department of the Army. Office of the Assistant Chief of Staff for Installation Management.