DISCUSSION OF REPORT AND SUPPLEMENTARY STUDIES: EFFECT OF REINFORCEMENT AS SHOWN BY COLUMBIA PIKE EXPERIMENTAL ROAD - SUMMARY OF REPORT

BASED ON COMPARATIVE SECTIONS, GRAVEL AGGREGATE, WITH AND WITHOUT CENTER JOINT, TWO HUNDRED FEET LONG AND 4 YEARS OLD, THE FOLLOWING CONCLUSIONS WERE MADE: (1) COMBINED LONGITUDINAL AND TRANSVERSE CRACK IN FULL WIDTH SECTIONS WAS REDUCED MOST CONSISTENTLY WITH SLAB THICKNESS THAT WAS EITHER ONE SEPARATELY, (2) PLAIN HALF-WIDTH SECTIONS CONTAINED NO MORE TRANSVERSE CRACKS THAN DID FULL WIDTH SECTIONS, (3) MESH REINFORCED SECTIONS CONTAINED CONSIDERABLY LESS CRACKS THAN PLAIN SECTIONS, (4) BONDED LONGITUDINAL REINFORCEMENT OF LESS TENSILE STRENGTH THAN THAT OF CONCRETE WAS MORE OR LESS RUPTURED AT OPEN TRANSVERSE CRACKS, BUT DID NOT CAUSE CORNER BREAKS OR FINE TRANSVERSE CRACKS IN THE SLAB, (5) LARGE AMOUNTS OF LONGITUDINAL STEEL IN BOND CAUSED EXCESSIVE TRANSVERSE CRACKING IN CORNER JOINTS, (6) TRANSVERSE STEEL ACROSS LONGITUDINAL JOINTS HELD THE SLABS TOGETHER AND PREVENTED SPALLING, AND (7) SECTIONS WITH 3/8 INCH TRANSVERSE RODS CONTAINED MORE TRANSVERSE CRACKS THAN SECTIONS REINFORCED ONLY LONGITUDINALLY. IT WAS FOUND THAT SUBGRADE RESISTANCE TO PAVEMENT CONTRACTION AND LONGITUDINALLY REINFORCED PAVEMENTS AFTER BEING CARRIED ACROSS TRANSVERSE CRACKS BY THE STEEL WAS TRANSFERRED TO THE CONCRETE AT A RATE DEPENDING ON BOND AND STRENGTH OF CONCRETE. THIS DISCUSSION OF LONGITUDINAL REINFORCING APPLIES ONLY TO STEEL BONDED FOR DISTANCES.