NEW DELHI (Metro Rail News): The northern part of India is experiencing an unprecedented cold wave, which has slowed down construction works in the region. However, the construction of the Delhi-Ghaziabad-Meerut RRTS corridor is still progressing at a rapid pace with the use of a particular technique. Pre-casted segments of the tunnel rings, used for constructing the underground section of the corridor, are being manufactured at a pace with the help of ‘Steam Curing Technology‘ at the casting yard of NCRTC.
Tunnel segments are being cast at the casting yard of NCRTC with assured quality control. However, with the onset of winter, precasting the segments faced a challenge. Due to low temperatures, the segments moulded by the machines do not get early strength in the stipulated time frame. As a result, the concrete, bars, and other construction materials used in the segment do not reach their actual solid state on time. The segments must be substantial and robust with the required strength to be used in tunnel construction. Therefore, NCRTC uses the steam curing technique to strengthen and solidify precast segments in low-temperature climates rapidly.
Under the steam curing technique, the newly formed segments are steamed for 5 to 7 hours with the help of a boiler. This allows the newly formed segments to solidify in their concrete structure and gain early strength almost three times faster.
Typically, when the temperature is below 10 degrees, it takes a regular precast segment about 40 to 45 hours to solidify. However, the steam curing technique completes the same work in about 10 hours. This way, with the help of this technology, the pace of construction of the tunnel rings continues despite the changing weather and construction of the RRTS corridor continues to progress at a pace. In addition, as the newly constructed segments automatically gain early strength in higher temperatures, this technique is not required in summer.
In the underground section in Delhi, the construction of two parallel tunnels of about 3 km in length from Anand Vihar station towards New Ashok Nagar and about 2 km towards Sahibabad is in full swing. For the construction of these two parallel tunnels, four Sudarshan are constructing about 10 km tunnel, out of which more than five and a half km tunnel construction has been completed. About 25,600 tunnel precast segments have been used so far in Delhi. In Meerut, a total of 11 km parallel tunnel is to be constructed, out of which about 5 km tunnel has already been constructed and about 21,000 tunnel precast segments have been used. These tunnel rings are manufactured at the casting yard of NCRTC with assured quality control.
NCRTC has been using precast segments for construction since the project’s inception. Precasting helps in the safe and speedy execution of construction work while ensuring better quality control and reducing air and noise pollution. Therefore, the decision to adopt precasting technology was an important strategic decision.
NCRTC aims to open the entire Delhi-Ghaziabad-Meerut corridor to the general public by 2025. Before this, the 17-km long Priority Section between Sahibabad to Duhai of the Ghaziabad region will be operationalised this year for the public.