Papers by Author: Sean Morefield

Abstract: A large scale atmospheric corrosion monitoring test was undertaken for the purpose of characterizing environmental severity. This work was conducted at ground based Army, Navy, Coast Guard, and Air Force sites. At present over 73 sites are in operation. This work adds to the existing worldwide databases to include new military and/or related sites not previously monitored. In addition and to the extent that such data are available, relevant weather data was collected from public or military sources in order to test existing corrosion algorithms for each site. Many of the 1 year exposures have been successfully completed. However, all of the exposures currently in progress will not be completed until early 2008. Sample analyses are in progress. New data have been obtained to show the important effects of sheltering on reducing corrosion rates. Data from Daytona Beach and Tyndall AFB show that even a relatively simple open structure/sunshade can reduce corrosion rates by factors of 2 or 3. New data are being reported on corrosion vs. distance from ocean. Data were also collected for the comparison of corrosion severity among commonly used test sites and within selected sites (multiple locations within a base.)

Abstract: U. S. Army Corps of Engineers Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC-CERL), and Carlyle Consulting’s John Carlyle conducted a leak detection survey at a U.S. Army Installation. The age of pipes in the distribution system ranged from 20 to 60 years. The thrust of the work was to acoustically survey all of the underground pipelines constituting the installation’s potable water distribution system and find any leaks. The results of the survey were that 6 leaks were discovered in the main lines, 63 leaks associated with fire hydrants, freeze proof hose bibs, water meters, etc., and 33 leaks inside buildings. Over two thousand acoustic measurements were made in order to obtain these results.

Abstract: In below-grade buildings and buried structures, such as those constructed as hardened secure facilities and used for munitions storage on U.S. Army installations, water intrusion can cause serious damage and reduce penetration resistance. Inside the building active water and high humidity can result in corrosion of HVAC, electronic equipment, as well as damage or disrupt mission critical electronic equipment. In the adjacent backfill and the structure itself, excessive water can seriously compromise the structural hardening of the facility. Thus, it is vital to Army sustainability to control moisture in below-grade structures and eliminate corrosion of electrical mechanical equipment. This also prevents mold growth on the interior surface of below grade concrete walls and floors. Control of water movement involves both actively removing water in and around a building, and the use of barriers to prevent water from penetrating to interior spaces. A pumping system is typically required with the use of a barrier system to assist in controlling the movement of moisture into the structure. Conventional waterproofing technologies are expensive and often have short service life. A new approach is needed—a cost effective and robust solution—to the pervasive problem of water intrusion. Electro-Osmotic Pulse is a promising alternative solution presented here. Electro-Osmotic Pulse (EOP) technology uses pulses of electricity to reverse the flow of water seepage. The applied voltage causes moisture to flow out of the basement walls and away from the building. The technology works by alternately pulsating a direct electric field with an off period. The first part of the sequence consists of a pulse of positive voltage (as seen from the dry side of the concrete wall), followed by a pulse of negative voltage. This is followed by a period when no voltage is applied. Of the three parts, the positive voltage pulse has the greatest time duration. The amplitude of the positive signal is typically on the order of 20 to 40 Volts DC. This electrical pulse causes cations (e.g., Ca++) and associated water molecules to move from the dry side (anode) towards the wet side (cathode) against the direction of flow induced by the hydraulic gradient, thus preventing water penetration through buried concrete structures. Laboratory and field tests have shown an increase in calcium compounds at the cathode side of test specimens. The negative portion of the pulse increases the efficiency of moisture movement by depolarizing the electrodes. Electro-Osmotic Pulse (EOP) technology has been successfully installed in military structures such as family housing, steel reinforced deep structures, and tunnels. EOP has also been implemented on Civilian structures such as residential structures, D.C. Metro Tunnels, and an underground treasury vault. EOP has been shown to prevent moisture seepage into below-grade structures. It is effective at keeping concrete surfaces at or below 50 percent humidity content, meaning the treated space stays dry, indoor relative humidity stays low, and no mold or mildew can grow. This technology has received the 2002 international NOVA award for innovation in construction, and twice nominated for the CERF Pankow award (1999 and 2004). The ERDC research on this technology has also been recognized by the 2004 Army Research and Development Achievement Award.