Posted Jan 17, 2008, 4:10 PM
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mmmmkay
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Join Date: Dec 2007
Location: Colorado
Posts: 329
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Quote:
Originally Posted by 10023
I know it's too much to ask for, but raw concrete for the balconies would be amazing. Why can't American contractors do it like they do in Japan, with the machines that vibrate the concrete gently as it sets for no bubbles and smooth surfaces and a clean finish?
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We can if they want to spend the money on a more expensive mix. Imagine concrete that flows like water and you have SCC 
If someone would take a close up of the slab we might find that they are already using SCC for this project. From a distance they do look rather clean.
Quote:
Self-consolidating concrete, also known as self-compacting concrete and SCC, is a highly flowable, non-segregating concrete that can spread into place, fill formwork and encapsulate even the most congested reinforcement, all without any mechanical vibration. As a high-performance concrete, SCC delivers these attractive benefits while maintaining all of concrete's customary mechanical properties and durability characteristics.
SCC is defined as a concrete mixture that can be placed purely by means of its own weight, with little or no vibration. Adjustments to traditional mix designs and the use of superplasticizers creates flowing concrete that meets tough performance requirements. If needed, low dosages of viscosity modifier can be used to eliminate unwanted bleeding and segregation.
Since its inception in the 1980s, the use of SCC has grown tremendously. The development of high performance polycarboxylate polymers and viscosity modifiers have made it possible to create “flowing” concrete without compromising durability, cohesiveness, or compressive strength. The flowability of SCC is measured in terms of spread when using a modified version of the slump test (ASTM C 143). The spread (slump flow) of SCC typically ranges from 18 to 32 inches (455 to 810 mm) depending on the requirements for the project. The viscosity, as visually observed by the rate at which concrete spreads, is an important characteristic of plastic SCC and can be controlled when designing the mix to suit the type of application being constructed.
SCC's unique properties give it significant economic, constructability, aesthetic and engineering advantages. SCC is an increasingly attractive choice for optimizing site manpower (through reduction of labor and possibly skill level), lowering noise levels, and allowing for a safer working environment. SCC allows easier pumping (even from bottom up), flows into complex shapes, transitions through inaccessible spots, and minimizes voids around embedded items to produce a high degree of homogeneity and uniformity. That's why SCC allows for denser reinforcement, optimized concrete sections and shapes, and greater freedom of design while producing superior surface finishes and textures.
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