A $1-billion road and railway tunnel project under the Suez Canal is a key component of an Egyptian government plan to stimulate economic development in the Sinai region. Canada’s Xypex water-proofing products were an integral part of the project, controlling seepage through concrete tunnel segments so that construction could be completed on time.
Before the tunnels opened in spring 2019, vehicles waited for days to cross the canal by ferry or waited hours at a single bridge or tunnel. Four new road tunnels have reduced canal crossing times to just 10 minutes and the two-lane roadways carry up to 50,000 vehicles per day in each direction.
In January 2018, the last of four tunnel boring machines emerged from its 13.02-metre diameter hole on the eastern bank of the Suez Canal. The 4.8-km tunnel is one of two tunnels dug side by side under the canal just north of Ismailia to create the new highway linking the Sinai Peninsula with Egypt’s prosperous Nile Valley.
Two 2.8-km highway tunnels were also completed simultaneously south of Port Said. A total of 15.2 kms of road tunnels were dug below the canal, reaching depths of more than 60 metres.
A single-layer precast concrete segmental lining was installed in all four tunnels. Nine precast concrete tunnel lining segments were required to create a single lining ring, with precast base platform elements supporting the road deck. More than 1.5 million cubic metres of high-strength concrete were used to cast more than 72,000 lining segments. Elastomeric gaskets were built into the lining segments to provide a watertight seal.
In 2018 and early 2019, as round-the-clock work continued on the four tunnels to meet the target opening dates, water seepage was detected in some sections that were experiencing hydrostatic pressures of up to 6 bar.
To solve this challenge, the contractors ordered 1,814 kg of Xypex Concentrate, based on a specification provided to consultants ACE Moharram-Bakhoum by Beton Waterproofing Services, the Xypex distributor for Egypt.
“We investigated several ways to apply the Xypex Concentrate to the joints to achieve optimal results,” says Amr Saad, general manager for Beton. “The Xypex crystalline waterproofing material needs time to diffuse into the concrete substrate, so we modified our specification to recommend that the waterproofing contractors apply the Concentrate as a thick paste for best results.”
The active chemicals in Xypex Concentrate react with moisture and the constituents of the hardened concrete to cause a catalytic reaction. This reaction generates a non-soluble crystalline formation throughout the pores and capillary tracts of the concrete that permanently seals the concrete and prevents the penetration of water and other liquids from any direction, even under high hydrostatic pressure.
Xypex Concentrate not only permanently seals concrete and heals hairline cracks up to 0.4 mm, it also provides chemical resistance properties that mitigate the attack of chlorides and sulfates and the effects of carbonation and alkali-aggregate reaction.
Four subcontractors, one for each of the four highway tunnels, applied the Xypex Concentrate as needed. Saad notes that 95 per cent or more of the seepage was stopped using Xypex Concentrate.
“We are proud to have played a role in helping to provide the best possible waterproofing solution for this demanding application,” Saad says. “Our country is undergoing a tremendous cycle of construction and renewal. We continue to be involved in many projects across Egypt where contractors and owners want a proven water-proofing solution.”
This content is sponsored by Xypex in collaboration with ConstructConnect® Media. To learn more about Xypex, visit www.xypex.com.