Special thickening agent for NATM VISCO TOP UT

The amount of dust generated when spraying concrete in mountain tunnel operations is extremely high and has become a serious social issue, resulting in litigation over the damage it causes to the health of tunnel construction workers.In Japan, dust guidelines were revised in April 2021, amending the acceptable dust concentration from 3 mg/㎥ or less to 2 mg/㎥ or less. Further reinforcement of dust measures is becoming a challenge.

Accelerators are used in sprayed concrete due to the occurrence of what is called rebound.A large number of powder type accelerators are used in Japan due their superior strength properties; however, they also pose the problem of a large amount of dust generation.