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Mastour ReadyMix provides its customers with high-quality branded Ready
mix concrete and cement products for their construction needs |
Ready mix concrete is composed of standard concrete ingredients and
additives, according to the intended use of the concrete. “Ready mix” is
not a special type of concrete. Instead, the term describes the way the
concrete is delivered to a job site–already mixed. Ready mix concrete
is the solution to the problem of having to mix concrete components in
large quantities while maintaining consistently precise properties.
Features
By volume, ready mix concrete is compose of 60 to 75 percent
aggregate including sand, gravel and stone. Any clean, hard,
non-reactive, non-porous rock or sand may be a suitable aggregate. Size
and shape of aggregate are selected according to the desired strength
and texture of the concrete, how the ready mix concrete will be placed,
and also cost.
Function
Cement is the binder in ready mix concrete, and it represents 10 to
15 percent of ready mix concrete volume. The most commonly used cement,
Portland cement may contain limestone, marl, shale, blast furnace slag,
silica sand and iron ore. Ingredients may vary; it’s the chemical
constituents of these–calcium, silicon, aluminum, iron and gypsum–that
are important in ready mix concrete.
Effects
The components of ready mix concrete cannot become solid without
water. Water molecules, when combined with calcium silicate, react in a
chemical process called hydration. The hydrated compounds of water and
calcium silicate form a dense crystaline structure that binds the
aggregate into a single solid form. So technically concrete does not
dry. Instead, it cures chemically.
Significance
The ratio of water to cement in ready mix concrete is the critical
determining factor in concrete strength. Water not used up by the
hydration reaction remains a part of the concrete, causing it to be less
strong. Ideally, only enough water would be added to the mix to react
with the cement, and no more. In practice though, this makes for
concrete that is difficult to work with, so more water is added than
necessary for hydration. Depending on the intended use, ready mix
concrete is composed of 15 to 20 percent water by volume.
Potential
Ready mix concrete may also contain fly ash, silica fume, blast
furnace slag or metakaolin as a substitute for a percentage of the
Portland cement. These components, like Portland cement, react with
water to form a monolithic solid. The advantage of their use is the
improvement of concrete strength and durability. Fly ash, silica fume
and furnace slag are byproducts of power generation or industrial
processes, so their use benefits the environment by reducing waste.