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|Title:||Evaluation of Kaiser XM19 waterproof aluminum honeycomb landing mat with D and D1 connectors|
|Authors:||United States. Army Materiel Command.|
Carr, Gordon L.
|Keywords:||Honeycomb landing mats|
Kaiser landing mats
XM19 landing mats
|Publisher:||U.S. Army Engineer Waterways Experiment Station.|
Engineer Research and Development Center (U.S.)
Abstract: The investigation reported herein was conducted to evaluate a waterproof version of XM19 landing mat. The XM19 mat with water seals was designed and developed by Kaiser Aluminum and Chemical Sales, Inc., Oakland, Calif. The mat described herein is identical with standard XM19 mat, except that the connectors have been redesigned for insertion of water seals. Individual panels are joined along two longitudinal edges by hinge-type male/female connectors, with the male connector containing a neoprene compression seal inserted and bonded along the length of the connector. The adjacent two transverse connector edges of the mat are symmetrical and contain slots into which an aluminum-neoprene seal bar and an extruded aluminum locking bar are placed after the mat has been laid to form a waterproof joint. Laboratory, blast, and traffic tests were conducted on three versions of the XM19 waterproof mat. The traffic tests were conducted using a 25,000-lb F-4C single-wheel load with a tire inflation pressure of 250 psi. The tests were conducted both inside a hangar for protection from the elements and in an exposed area in which the tests were conducted over a six-month period with the mat subjected to both natural and simulated rainfall. The following specific results were obtained: (A.) The type 1 mat (D connector) permitted excessive deflection, inducing stresses and breaks in the panels, and the test was stopped at 500 coverages on a subgrade with a rated CBR of 4.6. (B.) The type 2 mat (D1 connector without water seals), tested under controlled subgrade conditions for comparison with most previous mat data, withstood the 25,000-lb, single-wheel load for 2000 coverages on a subgrade with a rated CBR or 4.1, which equates to 1785 coverages on a subgrade with a strength of 4 CBR. This exceeds the Qualitative Materiel Requirement (QMR) of 1000 coverages on a 4-CBR subgrade by 78.5 percent and is essentially equal to the service life of the standard XM19 mat. (C.) The waterproofing capabilities of the type 3 mat (D1 connector with water seals) were demonstrated on both low-strength (4 CBR) and high-strength (27 CBR) subgrades. Prior test data indicated that similar mat would not withstand 50 coverages in rainy weather, but the type 3 mat withstood 642 and 1668 coverages on subgrades of low and high strength, respectively, over a six-month period during which a total of 55.24 in. of rainfall (natural and simulated) was recorded. (D.) The placing rates for the types 1 and 2 mats were 414 and 441 sq ft per man-hour, respectively, on a flat subgrade. The maximum placing rate obtained for the type 3 mat in three tests was 66.4 sq ft per man-hour on a 2 percent crowned subgrade; however, the rate for placing the type 3 mat using improved placing tools was 174 sq ft per man-hour on a flat subgrade. (E.) The antiskid coating provided a surface that yielded a coefficient of friction of 0.52 for both wet and dry surfaces and that produced only slight tire wear. (F.) The type 3 mat withstood the blast temperature test as specified by the QMR for medium-duty mat (300 °F for 5 sec) without loss of structural strength or damage to the seals. (G.) The seal bars were damaged both during traffic and during the removal operation and were not reusable. For adequate performance, it is not considered desirable to reuse any of the seal bars. All locking bars were reusable except those damaged during removal. It is recommended that further efforts be made to improve both the placing rate and the removal rate of the waterproof mat. NOTE: This file is large. Allow your browser several minutes to download the file.
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