A.50mm B.60mm C.70mm D.80mm
预应力混凝土轨枕是在浇灌混凝土前对所配的钢筋施加拉力,当浇灌混凝土有一定强度后,从轨枕两端切断钢筋。
A.100mm B.80mm C.50mm D.20mm
A.50 B.80 C.100 D.120
A.50mm B.20mm C.10mm