Yifu High-Speed Railway, China Railway Shanghai Bureau

Background

Section 13 of the Yichang–Fuling High-Speed Railway in Hubei Province, constructed by China Railway Shanghai Engineering Bureau, is located in Enshi City, Hubei.On site, the initial tunnel lining is sprayed with C30 ultra-early-strength shotcrete. Because this mix sets much faster than conventional shotcrete, controlling its viscosity and cohesion is more difficult. Even a slight deviation in the dosages of water-reducer or accelerator can cause rebound to jump sharply, wasting material and compromising the density and uniformity of the sprayed layer.

Fig. 1 On-site spraying of ultra-early strength shotcrete in Yifu high-speed railway tunnel

Project challenge

Conventional shotcrete sets relatively quickly, yet its early-strength gain is slow: the one-day strength is only about 10 MPa. Ultra-early-strength shotcrete, in contrast, not only sets even faster but also develops strength far more rapidly, greatly improving construction efficiency on site.

Solution from ARIT

When ARIT water reducing admixture is combined with an accelerator, C30 shotcrete attains over 1.5 MPa at 3 h and 10 MPa at 8 h, while rebound is cut by more than 50 % compared with conventional shotcrete.

Product from ARIT

ART-SL16, ART-611C

For detailed remixing formula, feel free to contact technicians of ARIT.