Rigid polyurethane foam testing for mine neutralization and vehicle traction performance

• Published in: Journal of terramechanics 2000-04, Vol.37 (2), p.87-98
• Main Authors: Mason, G.L., Green, J.G., Hall, K.G., Durst, B.P.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; Explosives; Geotechnics; Liquids; Materials testing; Miscellaneous; Polyurethanes; Soils; Tanks (military); Traction (friction)
• ISSN: 0022-4898; 1879-1204
• DOI: 10.1016/S0022-4898(99)00015-4

A rigid polyurethane foam (RPF) was dispensed on a test lane to determine if (1) a trafficability lane could be created that would neutralize vehicle and personnel mines and (2) the foam would increase vehicle traction in slippery soils. The RPF consisted of two liquids, 1,1-dichloro-1 -fluoroethane (known as urethane resin) and polymeric diphenylmethane diisocyanate (known as polymeric MDI). These two liquids were mixed in a commercial foam dispensing machine and dispensed at the test site. Two test areas were built to examine minefield neutralization and traction improvements separately. The minefield test lane consisted of a 7×17 m area, instrumented with pressure cells, M15 training mines, M1 tripwire devices and string tension sensors covered with approximately 0.6 m of 64.1 kg/m 3 density RPF. Fifty passes each of an M88A2 and a HMMWV were made while engineers monitored changes in ground contact pressure. Trip wires were placed 5 cm above the ground in the lane and instrumented to measure tension placed on the devices by the expanding foam. Application of the RPF, at a depth of 0.6 m, appeared to neutralize most antitank mines examined in this program but triggered all the trip wire devices during the application. The foam also appeared to stand up well under vehicle traffic. The traction test lane consisted of two 5×35 m lanes. The lanes were created to test changes in traction in dry, wet, and foam-augmented wet soil. For these tests, 0.08 to 0.1 m of foam was dispensed into M88A2 and HMMWV ruts created during dry and wet drawbar-pull tests. Trafficability performance of the M88A2 decreased slightly with the application of the foam from an optimum drawbar pull coefficient of 0.21 after the simulated rainfall to 0.14 after application of the foam. Trafficability of the HMMWV showed moderate improvement from an optimum drawbar pull coefficient of 0.3 after the simulated rainfall to 0.5 after the application of the foam.