Self consolidating concrete history

self consolidating concrete history-39
It is defined as a concrete mix that can be placed purely by means of its own weight, with little or no vibration.As a high-performance concrete, SCC delivers these attractive benefits while maintaining all of concrete's customary mechanical and durability characteristics.

The J-ring test is a variation to the slump flow, where a simulated rebar cage is placed around the slump cone and the ability of the SCC mix to spread past the cage without segregation is evaluated.

The U- box, L-box and J-ring tests measure the passing ability of concrete in congested reinforcement.

Another test being standardized is a column test, which measures the coarse aggregate content of concrete at different heights in a placed columnar specimen as an indication of stability or resistance to segregation.

Self-consolidating concrete is a highly flowable type of concrete that spreads into the form without the need for mechanical 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 eliminate unwanted bleeding and segregation.One of the most remarkable projects built using self-compacting concrete is the Akashi-Kaikyo Suspension Bridge.In this project, the SCC was mixed on-site and pumped through a piping system to the specified point, located 200 meters away.In certain instances the addition of superplasticizers and viscosity modifier are added to the mix, reducing bleeding and segregation.Concrete that segregates loses strength and results in honeycombed areas next to the formwork.Several test procedures have been successfully employed to measure the plastic properties of Self-Consolidating Concrete.The slump flow test, using the traditional slump cone, is the most common field test and is in the process of being standardized by ASTM.This type of concrete must meet special project requirements in terms of placement and flow.Self-compacting concrete with a similar water cement or cement binder ratio will usually have a slightly higher strength compared with traditional vibrated concrete, due to the lack of vibration giving an improved interface between the aggregate and hardened paste.Self-compacting concrete is a non-segregating concrete that is placed by means of its own weight.The importance of self-compacting concrete is that maintains all concrete’s durability and characteristics, meeting expected performance requirements.

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