(South Africa) — A new South African Roller Compacted Concrete record will be set when more than 1.12 million cubic meters of concrete will be placed. The record breaking event will be set on De Hoop dam on the Steelpoort River, in the Sekhukhune area, in Limpopo. The hourly pouring rate of the team is around 230 m3/h, with spurts of around 360 m3/h.
The wall will be made of RCC, stones, sands including a plasticizer added as needed; furthermore the faces of the steps are immersion vibrated. This removes the need to use a concrete skin against the shutters, which are oiled instead, providing a smooth finish with high strength, he explains.
Articulated dump trucks (ADTs) transport the concrete onto the dam wall, where it is spread out by a bulldozer into a 300-mm-thick layer and compacted by a 10 ton vibratory roller. The dam wall will be around 85 m high after completion, scheduled for October next year, and had reached half its final height in early November.
A unique hollow rebar is being developed at Oregon State University. The new design will produce and hollow composite rebar, consisting of a ‘load carrying glass fiber reinforced resin core, overmolded with corrosion, impact, and UV resistant carbon fiber reinforced outer shell’. CRT owns the exclusive license for the FRP composite rebar patented technology.
This hollow rebar is impervious, to the salt and concrete’s alkalinity, in other words it present a corrosion proof surface. The rebar has a higher tensile strength than steel while having one quarter the weight of steel and it is electromagnetically neutral. One significant advantage of the hollow rebar, is that it allows the use of the rebar as conduit for several applications.
The composition of the outer sleeve can include any resin that is compatible with and will bond to the vinyl ester resin core, and it can be reinforced with chopped carbon, glass and/or basalt fibers. The continuous-glass hollow inner sheath does the work of carrying loads.
By: Juan Rodriguez