Why buried concrete in Deira needs a different mix
Coastal Deira has a shallow water table, and that water carries chlorides and sulphates. Chlorides travel through concrete to the reinforcement and start corrosion; sulphates attack the cement paste itself. Piles, basement walls and rafts sit in that water for their whole life.
Our piling and substructure mixes for this exposure use GGBS blended with OPC, which lowers permeability and improves sulphate resistance, and a low water/cement ratio. Cover to the steel and the exposure class come from the consultant, and we design to them.
Basement rafts in this ground are often thick and heavily reinforced. GGBS also lowers the heat of hydration, which helps keep the core of a thick raft from running far hotter than its surface.
Excavating against older buildings
Many plots are tight against old buildings. Before the basement can be dug, a shoring wall of secant or contiguous piles holds back the ground. Our shoring mix is designed for that work: workable enough to tremie into a bored hole full of water, with the setting time the piling contractor needs.
Pile concrete is placed continuously. A 1 m pile 20 m deep takes about 16 m³, so two trucks per pile, and the second one has to be ready when the first runs out.
Hotels and refurbishment
Above ground, hotels need columns, cores and the occasional transfer slab where public floors meet room floors. Refurbishments in the souk area are the opposite: small pours, often by pump, with long boom reach over existing roofs. Trucks reach Deira over Al Maktoum Bridge or Al Garhoud Bridge, about 18 km from Al Quoz, so traffic dictates the timing.
On refurbishment jobs, new concrete often meets old concrete of unknown quality. Your engineer decides how the two connect; we supply the specified grade in the volume the job needs, from a few cubic metres upward.
Questions from Deira sites
- Do Deira foundations always need a GGBS mix?
- The consultant decides from the soil and groundwater tests. In coastal ground with chlorides and sulphates, a GGBS blend with a low water/cement ratio is the usual answer.
- Can you supply at night for a basement raft?
- Yes, the plant runs 24/7. Night pours keep placing temperatures down and avoid the worst bridge traffic.
- Which bridge do your trucks use?
- Al Maktoum Bridge or Al Garhoud Bridge, chosen by the time of day. We build the crossing into the retarder dose.