LABORATORY RESEARCH ON PAVEMENTS CONTINUOUSLY REINFORCED WITH WELDED WIRE FABRIC

Abstract

Since February 1955, research has been conducted at Purdue University on reinforced concrete pavements using welded wire fabric as the principal reinforcement. This research has been carried on in the Structural Engineering Laboratory of the School of Civil Engineering. The final techniques as used in the laboratory are presented. The specimens chosen were 28 feet long by 3 feet wide by 8 inches thick. The reinforcement consisted of either 6 x 12, 0/3; 6 x 12, OOOOO/O; or 4 x 12, OOOOO/O welded wire fabric. The specimens were cast in a portable form in which the amount of steel, the location of the steel, and the depth of slab could be varied. Each of the specimens was fabricated with preformed weakened planes in order that the slab would crack at definite locations in the test region. This permitted the measurement of strains in the fabric reinforcement at these predetermined cracks. The slabs were tested on an elastic subgrade having a modulus of approximately 160 pci. The subgrade was of such material that its modulus could be varied within reasonable limits. The slab specimens were loaded with vertical static loads to simulate traffic loads and horizontal loads to simulate stresses induced by temperature changes. Electric SR-4 strain gages were placed at various locations on the fabric to determine the stresses in the fabric. Vertical deflections of the slab were obtained by use of Federal dial indicators, and crack widths or surface strains in the concrete were obtained by use of a Whittemore strain gage.