REINFORCING BAR WITH HIGH MACHINABILITY AND TUNNEL BORING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a reinforcing bar remarkably improved in machinability and a tunnel boring method for boring a reinforced concrete using it in order to solve problems that the boring of reinforced concrete is extremely inefficient because of high resistance of reinforcing bar, and also, machinable carbon fiber reinforcement is extremely limited in application because of its expensiveness. ;SOLUTION: This reinforcing bar, prepared by stranding ≥5 pieces of steel wire which contains, by weight ≤0.5% C, ≤0.2% Si, 0.2-1.5% Mn, and 0.05-0.6%, in total, of S and Pb, or steel wire, containing 0.3-1.0% C, 0.6-1.3% Si, 0.3-1.5% Mn, ≤0.1% S, at least one component among 0.001-0.005% B and 0.03-0.30% Mo, and further 0.2-1.0% graphite, and desirably has a grain size of No.5 or below and ≤9mm diameter.;COPYRIGHT: (C)1997,JPO