Start with a little about cement and end with our rocks ph test results.
General Cement
How Cement Works...
Background
Concrete is made by the combination of cement, water, and aggregate of various sizes to make a workable slurry that has the consistency of a thick milk shake.
Name Percent by
Weight Chemical Formula
Tricalcium silicate 50% 3Ca0 SO2
Dicalcium silicate 25% 2Ca0 SiO2
Tricalcium aluminate 10% 3Ca0 Al2 O3
Tetracalcium aluminoferrite 10% 4Ca0 Al2 Fe2 O3
Gypsum 5% CaSO4 H2O
The binding quality of portland cement paste is due to the chemical reaction between the cement and water, called hydration. Portland cement is not a simple chemical compound, it is a mixture of many compounds. Four of these make up 90% or more of the weight of portland cement: tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. In addition to these major compounds, several other play important roles in the hydration process. Different types of cement contain the same four major compounds, but in different proportions.
The cement in concrete needs water to hydrate and harden. Even though the chemical reactions may be complete at the surface of the concrete, the chemical reactions at the interior of the concrete take much longer to complete. The strength of the concrete keeps growing as long as the chemical reactions continue.
When water is added to cement, the chemical reaction called hydration takes place and contributes to the final concrete product. The calcium silicates contribute most to the strength of concrete. Tricalcium silicates are responsible for most of the early strength (first seven days).
The original dicalcium silicate hydrates, which form more slowly, contribute to the strength of concrete at later stages. The following word equations describe the production of concrete.
Tricalcium silicate + Water
(yields)
Calcium silicate hydrate + Calcium hydroxide + heat
Dicalcium silicate + Water
(yields)
Calcium silicate hydrate + Calcium hydroxide + heat
Of the five chemical reactions important for providing the strength for concrete the above reactions are the most important.
The two calcium silicates, which constitute about 75% of the weight of portland cement, react with water to form two new compounds: calcium hydroxide and calcium silicate hydrate. The latter is by far the most important cementing component in concrete. The engineering properties of concrete—setting and hardening, strength and dimensional stability—depend primarily on calcium silicate hydrate gel. It is the heart of concrete.
When concrete sets, its gross volume remains almost unchanged, but hardened concrete contains pores filled with water and air that have no strength. The strength is in the solid part of the paste, mostly in the calcium silicate hydrate and crystalline phases.
The less porous the cement paste, the stronger the concrete. When mixing concrete, therefore, use no more water than is absolutely necessary to make the concrete plastic and workable. Even then, the water used is far more than is required for complete hydration of the cement. The water-cement ratio (by weight) of completely hydrated cement is about 0.22 to 0.25, excluding evaporable water.
PH of HOT, CURING AND CURED CEMENT...
From our own testing using our rocks in distilled water.
Day one -24 hours after rocks made ph-12.5-13.5
Day two-48 hours after rocks made ph 10.5-11.9
Day three- ph 9.0-10.8
Day four - ph 9.0-10.0
Day five- ph 8.6-9.8
Day six- ph 8.4-9.5
Day 14 - ph 8.2-9.0
Day 21 - ph 8.0-8.6
Day 28- ph 8.0-8.2
Day 35 ph 8.0-8.2
We normally keep our rocks dry misted, during the first 7 days, meaning they are left out in open, and have water misted on them
daily for the first 2 days. Then they sit dry for the next 5 days. At this point they are put in buckets, or offshore for final curing and
hardness increasing by being submerged in water.
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Who uses our products?
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