About Pozzolanic Sand
 

POZZOLANS are a vital component in concrete production, extending the durability of our major infrastructure from Decades to Centuries.

Fossil fuel by-product pozzolans, like fly ash, have been widely used to improve concrete performance and durability over the last fifty years, but as cost and environmental pressures increase on the coal-burning industries, producers are turning to supply of natural pozzolans. 

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PORTLAND CEMENT, the powder that serves to bind rocks and sand in concrete, is one of the largest contributors to greenhouse gases in the world as the process consumes large amounts of energy, usually a fossil fuel in one form or another. As the limestone is heated, it further releases carbon dioxide in forming the key reactive components in cement.  As concrete is the most widely used material in the world, the production of portland cement accounts for approximately 8% of all carbon emissions worldwide.

Concrete’s incredible design flexibility, strength and durability, save resources due to longevity of structures and reduced waste compared to other materials. Thus, while concrete is not going away, there are ways to reduce the carbon footprint created by cement.

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1) NATURAL POZZOLAN is a highly functional and beneficial greenhouse gas reduction agent in the concrete industry. Each kilo of cement displaced provides almost equal reduction in greenhouse gases emitted. 
 

2) NATURAL POZZOLAN is a valuable cementitious material that helps produce denser, stronger, more durable concrete and as compaction is complete, it keep water out to
eliminate any rusted reinforcement - "concrete cancer" through structures whether in your
backyard, city apartments and office buildings, or an airport runway.

3) NATURAL POZZOLAN will mitigate or eliminate unsightly efflorescence in concrete, the unsightly and potentially damaging white powdery substance that forms on the surface of some concrete products often exposed to wetting and drying. 
 

ANCIENT HISTORY
Rome is well known as the "Eternal City".Ancient Romans architects
understood the benefits of pozzolans, they took full advantage of the
qualities provided to concrete construction. The "eternal" nature of
concrete produced was a result of their understanding of how to use
a high quality natural pozzolan in construction.

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MODERN USE EARLY IN THE 20TH CENTURY,

Engineers rediscovered pozzolanic materials  as they researched

ways to provide permanence and strength to the massive dam projects. 

The concrete of that time, using only Portland cement, had many disadvantages and created concerns about the durability of these massive structures. Issues related to heat of hydration, chemical attack, and overall durability were of great concern to these engineers, and they contemplated how to insure that their huge concrete structures would withstand the various inherent challenges.

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FLY ASH POZZOLANS - the technical standard for pozzolans,
ASTM C618, identifies classes of fly ash—Class F and
Class C – along with Class N designated for natural pozzolans.

The classes of fly ash are distinguished by differences in
chemical composition, usually determined by the types of coal from which they come.

Class F fly ash is generally produced from burning anthracite or bituminous coals,

while Class C fly ash typically comes from sub-bituminous sources.

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This is important for two reasons – First, Class F fly ashes tend to work better than Class C fly ashes in providing long term concrete durability through protection against various chemical attack mechanisms.

 

Depletion of Carbon FLY ASH - Fly Ash has functionally served as a natural pozzolan replacement for many decades now, times are changing: coal fired power plants are in steady decline, those in operation are increasingly producing lower volumes of fly ash and many plants that continue to burn coal are being forced to install pollution control measures that make the ash technically or economically infeasible for use in concrete.

 

This conundrum for fly ash use, widely acknowledged as a success story in recycling, infrastructure improvement and greenhouse gas reduction, is the basis for the
resurgence in natural pozzolan use. Of the many new power plants currently on the drawing boards, the vast majority targeted globally for exclusion of combustion-based plants are to be powered by cleaner-burning gas.  One after another, coal-fired plants are being shuttered or are being retrofitted for cleaner-burning fuels in the future, further squeezing an already tight fly ash supply.

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Given this situation, we believe the case, both business and environmental, has already been made. A clear return to the original standard of natural pozzolans for improving concrete is the logical choice. In fact, as design specifications for many important infrastructure projects now require the use of pozzolans in concrete, the production of natural pozzolans like Claystone International Sand,  we believe will become more necessity than choice.