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Order Just The Concrete You Need
One of the most difficult concerns when ordering concrete in Portland is to order the correct amount.
Generally, contractors liberally estimate the amount of concrete they need for a particular job, then order an
overage of perhaps 10 to 20 percent. The biggest problem comes if the order comes up short. Generally, it
takes at least a day, sometimes even more, to schedule another order. This will add a significant delay to the
construction schedule, and additionally limit certain types of work where the concrete cannot be poured in
stages. It can also extend the construction time onto a day when the weather is very different, effecting the
cure of the concrete. This is especially true if it begins to rain.
For this reason, most projects end up using somewhat less concrete than they ordered. With the price of
concrete, this can add significant costs onto a budget. In addition, some companies charge for the disposal of
the extra concrete, incurring still more charges. The good news is that a contractor or homeowner can choose
a concrete supplier that will charge for only what is used. This makes it much easier to get just the right
amount of concrete.
Two types of companies will offer this service. The first are firms which specialize in small load concrete
deliveries. Often, they will work to combine customers so that a single delivery can satisfy several clients at
once. Others employ special delivery trucks that do not require a concrete premix. These trucks carry the raw
concrete ingredients ? concrete cement, aggregate, and additives ? and mix them to specifications on site.
These vehicles are able to provide the right mix of concrete at the right quantity on demand. In fact, if the
amount of concrete specified is insufficient, they can increase it at the time of delivery. This additionally
allows the concrete supplier to combine clients with different concrete mix requirements, making the
deliveries even more efficient. This increases the cost savings for the operation, which they can pass down to
the customer.
Other concrete specifications include the mixing ratio. Often, these are offered in particular mix designs for
specific applications. One of these is controlled density fill (CDF) concrete, which is a mix resulting in a
compressive strength of 1200 psi maximum. This is used in the common application of backfill in a
construction project. In this application, it is self-compacting and cementitious, making it easier to install,
cheaper, and stronger. In addition, it is easy to deliver, safer for the construction workers, and ready to use
much more quickly. Inspectors often wave or reduce inspection requirements when CDF is employed. Finally,
although it is a stronger material, it is easy to excavate if needed.
Another common mix design is shotcrete. Rather than being poured, shotcrete is actually pumped
pneumatically through a hose and shot at high velocity onto the target surface. This is a common
construction technique for pools. For this application, shotcrete is the wet-mix version of the concrete, and
gunite is used to refer to the dry-mix before it is combined.
If necessary, concrete color can also be specified. For choosing colors, one de facto color standard is the
Davis spectrum of concrete colors.
With these specifications, both contractors and homeowners can specify the small loads of they need.
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