United Concrete & Gravel Ltd. produces ready-mix concrete at our 3 batch plants located in Quesnel BC, Williams Lake BC and 100 Mile BC. Ready-mix concrete is a precise mixture of cement powder, gravel, water and admixtures. Your concrete arrives in a truck mounted mixer in a plastic or unhardened state. The ready-mix concrete is then placed into forms on the job-site and finished. Ready-mix concrete will harden in a matter of hours.
Concrete Where You Need It
Ready-mix concrete can be unloaded out of the mixer truck via chutes which are attached to the back of the mixer truck, which typically reach approximately 12 feet. Ready-mix concrete can also be unloaded into a pumper truck, which uses a boom and hose to place the ready-mix concrete. A pumper truck is required for hard to reach projects. Typically a pumper truck can reach 110 feet or more.
Ready-mix concrete is bought and sold by volume. A cubic yard of concrete is 3' long x 3' deep x 3' wide. A cubic meter of concrete is 1m long x 1m deep x 1m wide. Contact us and we will be happy to calculate your concrete measurements for you!
Residential and Industrial Concrete
From back yard patios, to commercial, or large industrial projects, United Concrete & Gravel Ltd.’s 3 batch plant locations, large fleet of mixers, and pumper trucks can serve almost any ready-mix concrete need.
READY-MIX CONCRETE - What do I ask for?
|Use||Recommended Compressive Strength||Slump||Air %|
|Basement walls & footings||25 MPa||3.5"||2-5|
|Basement floors||28 MPa||3.5"||2-5|
|Driveways, exterior steps, sidewalks *||32 MPa||3.5"||6-8|
*NOTE: All concrete exposed to applications of salt and freeze/thaw cycles should be air entrained.
Air entraining admixtures (AEA) are used to purposely entrain microscopic air bubbles in concrete. The AEA is added directly to the concrete materials either before or during mixing. Air entrained concrete contains millions of minute air bubbles that are distributed uniformly throughout the paste fraction of the mix. These bubbles must have a certain size and distribution to be effective. Natural or entrapped air bubbles are too large and spaced irregularly to be of any benefit. Air entrainment will dramatically improve the durability of concrete exposed to moisture during cycles of freezing and thawing. Entrained air greatly improves concrete's resistance to surface scaling caused by de-icing chemicals such as salt. The workability of fresh concrete is also significantly improved and bleeding and segregation are reduced or eliminated.
CSA Classes of Concrete
The following specifications listed are for the minimum strengths and minimum water to cementing materials (W/CM) ratio. The W/CM ratio is the total amount of water in the mix, including that in the aggregates, divided by the by the total weight of cementing materials in the mix, which include cement, fly ash, and silica fume. The mixes noted are for 20mm aggregate.
|Class||Strength (MPa)||Water/Cement Ratio||Air (%)|
|N||20||No requirement||No requirement|
Higher strength mixes and/or lower W/CM are often supplied, especially for classes F2, C4 and N.
It is critical to concrete’s long-term durability that it be kept as moist as possible for the first seven days after placement. In addition, it must be allowed sufficient drying time before being subjected to freezing temperatures or to de-icing salts. Curing concrete properly requires the correct control of moisture and temperature because without proper curing, concrete may only achieve 50% of its potential design strength. The logic behind the practice of a seven-day curing period rests on two facts:
Curing can be assisted in a number of ways:
A liquid curing agent is the most effective and convenient method. The curing agent should be applied as soon as finishing is complete. Curing agents form a membrane on the surface of the concrete in order to retain moisture. Once the curing agent has been applied, no further working of the concrete can be done. Use a spray or roller to apply curing agents.
According to CSA A23.1-94, curing is a mandatory part of concrete construction and requires moisture to maintain the concrete at 100% relative humidity and a minimum temperature of 10°C for a period of at least 3 days. This period is extended to a minimum of 7 days for the durability requirements of exposure classes F1, C1, C2, S1, and S2.
Cold Weather Concreting
Concrete can be placed safely throughout the colder months if precautions are taken. During colder weather, the mix should be adapted to the ambient temperature by heating the concrete, adding accelerators, and providing protection. From October 1st through April 15, United Concrete heats all concrete to meet the requirements of CSA and to maintain reasonable setting times and strength gain. High Early is an accelerating system, which decreases setting times during cold weather.
Concrete generates heat during hydration, the chemical process by which cement reacts with water to form a hard stable paste. Hydration is affected by initial concrete temperature, ambient air temperature, and the dimensions of the concrete and mix design. The temperature of the concrete during and after placement is critical since concrete sets more slowly as the temperature drops. Finishing and form removal may be delayed in cool weather and strength development can be impaired if appropriate precautions are not taken.
Do not place concrete on frozen ground, on snow, or in freezing weather. If concrete freezes while in a saturated condition, surface problems like scaling, spalling or cracking can arise due to the expansion and contraction of frozen water inside the concrete. During freezing weather, water curing of concrete should be terminated 12 hours before the end of the protection period. Do not use a curing agent if there is any chance that the concrete will freeze during the curing period.
This information has been provided to assist you with your cold weather construction. For a complete review of cold weather concrete practices, please refer to CSA A23.1 – 94 Section 21.
Plasticizers are admixtures that increase slump to make concrete easier to place. Plasticizers disperse particles of cement throughout a concrete mix. The effect is the same as adding water, but without the detrimental side effects. In addition, they reduce water in the mixture to gain higher, earlier strengths.
As a contractor, Plasticizers can help you to build more economically and to produce higher quality concrete at the same time, since moderately flowing concrete can be placed more easily providing good consolidation around rebar and tight forms with minimal vibration. Combine Plasticizers with low initial slump concrete to produce a workable mix with higher earlier strength.
Use Plasticized concrete for floors, suspended slabs, toppings, walls, columns, and anywhere that higher slump concrete is required. Our Dispatch Manager can help with this technical aspect of concrete mix design.
Contact us for a free estimate.
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