Precast Concrete Retaining Wall

A precast concrete retaining wall is normally used to retain earth or similar materials. It is also used to divide agricultural buildings such as a grain sheds or waste transfer stations to create storage bays.

Concrete retaining walls have gained in favour over in-situ concrete walls or timber walls and are very popular for civil engineering projects. They tend to be more economical, easier to install and more environmentally sound than other options. There are two main methods for fixing the retaining wall in place; embedding them into a concrete floor, or alternatively, using a ground fixing kit. The advantage of the latter solution is that the concrete retaining wall can be moved at a later date.

One of the most important things to consider when building a concrete retaining wall is the force at which the retained material is attempting to move forward and slide due to the force of gravity. This creates a lateral earth pressure behind the wall. Earth pressures will push the wall forward or overturn it if not properly looked at. Also, any groundwater behind the wall that is allowed to build up will cause an additional horizontal pressure on the wall. This problem can be solved by placing suitable drainage holes in the wall. While it can be an unwanted expense, getting a design from a structural engineer is very important and can save a lot of time and expense further down the line.

There are a range of products suitable for use as a concrete retaining wall. The most suitable product will depend on a number of factors including; the material retained, the height of the wall, site restrictions and budget. A few products that are worth considering; concrete panels (either used horizontally or vertically), L shape retaining wall units or concrete crib wall units. While the material costs can look expensive, after taking into account the savings in terms of installation, it often works out as the desired solution.

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Engineering an Empire - France 05:01

Engineering an Empire - France 05:01

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An Introduction to Silica Fume in Concrete Industry

INTRODUCTION
Today, Silica Fume is common for the production of concrete for large permanent structures, especially in aggressive environments, are exposed, as the structures of marine sciences.

It combines with Ordinary Portland Cement OPC (or Portland cement ASTM C150 Type I) as a substitute for sulphate resistant cement (Type V cement ASTM C150) in the production of sulfate resistance of concrete.

PRODUCTION
Silica fume is a byproduct of the silicone and reinforced concreteSilicone industry.

It arises from the reduction of quartize on silicon with high quality coal in an electric arc furnace.

Ovens revolve slowly on carbon electrodes. These create arc deep into the oven and then the high temperature required to produce, for fused silica.

The gas and air drawn in over the stove out from the fans some of the filter fabric. The decrease in silica fume in the filter and sent to the silos.

Particles of silica fume mediaSize is 0.1 microns. These particles are then 100 times thinner than a grain of cement.
Blowing air through the smoke of silica in the silo, the particles will affect the other particles and keep them from the forces of surface. This is basically the compression ratio for the production of densified silica fume, much more practical and easy to use in concrete.

TECHNICAL DATA FOR USE IN HIGH DURABLE CONCRETE:
The requirements for use in concrete are allocated generally in the form of:
SiO2 content:indicated by 85%
SiO3 content: maximum 1%
Loss on ignition: maximum of 6%
Humidity: 3%

The minimum wage SiO2 helps reduce the amount of pollutants and contaminants in the silica fume. The SiO 3 is limited for expansion, limiting the formation of Ettringite al. Moisture content of Silica Fume living conditions of the furnace is negligible in general. The limit of 3% is generous and will probably be of poor preservation. The standard specification for use inHydraulic cement concrete and the ASTM C1240.

ADVANTAGES OF USE FOR construction
The material was used throughout the world for many years in the area where a high strength and durable concrete have been applied.

Know-how to the production of concrete is essential still. Simply state must have a consistency of fresh concrete, so they are transported, can be made available and compact construction equipment, without separation. Use in combination with superplasticiser (for improvementwas the dispersion of cement and thus reduce significantly the demand for water supplied) is known worldwide for producing high quality cement. This will help to improve the properties of both fresh and hard concrete.

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