[In2] Self Compacting concrete

AUTHOR: Anna HoldenSelf compacting concrete- slump test
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Zaha Hadid Wolfsburg Science Centre- Self compacting concrete construction Zaha Hadid Wolfsburg Science Centre- Self compacting concrete construction Self compacting concrete diagram
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CROSSLINKS:

Database:
[Ec1][Ec2][In1]
[Sh1]
Prototypes:
[Hw]
Scenario Games: Action Plan:
[AP1]
External

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ACTORS/AGENTS

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DESCRIPTION
Self-compacting concrete is a relatively new product that is ideal for achieving enhanced finishes and compaction within complex geometries. It achieves this with the addition of a super plasticizer and a stabilizer, which are added to the concrete mix off site. The addition of these chemical-additives significantly increase the ease and rate of flow, enabling faster construction times and ease of workability. Self-compacting concrete is suitable for both in situ and precast construction. The super plasticizer makes the mortar softer and more flexible, allowing it to flow into the moulds without the need for vibration compaction.

The stabiliser is required to give the concrete mix more viscosity, so that when it is poured around reinforcement or obstacles, displacement of the aggregates is kept to a minimum, preventing the mortar and aggregate from separating. It also promotes compaction due to the increased weight of the mix ,which allows every part of the mould to be filled by means of the concrete’s self-weight. The additives enable the concrete to have a faster setting time. To prevent cold joints, it is therefore important that to have a continuous supply of mixture.

Phaeno Science Centre

Zaha Hadid Architects

The Phaeno Science Centre in Wolfsburg, Northern Germany, was designed on the basis that there would be a seamless transition between the vertical and horizontal elements of the structural system. In parallel with the use of self-compacting concrete, a unique structural system of complex geometries was used to establish the building as one complete architectural form. The structural system essentially consists of ten reinforced tapered concrete ‘cones’, rising from the basement car park to morph with and support a horizontal concrete floor slab.

Each cone varies in form, plan geometry, and height, with six cones entering into the main exhibition space and the remaining four continuing to support the steel roof structure. The cones convey the notion of dropped voids, which in parts provide additional floor space or act as access points to other floors. This provides a column-free space, creating a non-hierarchical system, not in terms of walls, slabs and columns, but instead shows the building structure as a whole entity. The first floor slab establishes changes in level by means of its waffle structure which folds within a 900 mm deep zone, creating changes in density and seamlessly folding into the vertical cone structures.

The finish and compaction of the complex concrete geometries were enabled by the use of self-compacting concrete and specialist timber forms. Timber, polystyrene, and metal forms were used to create forms to allow the cones to meet the floor with a flared geometry. Traditional concrete would not have allowed for adequate compaction, as the flow into the corners of the moulds would have been problematic and fitting vibrators up inside the shutters would have been time consuming and ineffective. This led to the use of self-compacting concrete, which was poured into the formwork in one continuous flow to prevent pour lines. Given the accelerated drying speed of self compacting concrete, this had to be done quickly and efficiently to fill pours of up to 7m high at 50 degrees from vertical. Due to the high volume of the pour, the shuttering was specially designed to account for increased pressure and the possibility of bleeding.

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RESEARCH AGENDA
Possibility of using SCC Technology with Lime hemp cement and fabric formwork.

Precedent research- Zaha Hadid Wolfsburg Science Centre