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Frequently Asked Questions

What is the difference between concrete and cement?

Most people don’t know the difference between concrete and cement and if asked they are likely to say something like, "I’ve never really thought about it but, aren’t they the same thing?" While cement and concrete are related they are nowhere near the same thing! Cement, which is the abbreviation of the correct name, "portland cement" is a fine grey powder that looks very much like gray flour. Most people have never seen cement. Concrete is a mixture of cement, sand, rock, water and small amounts of additives. Concrete is the material we encounter in our everyday lives.

The relationship between cement and concrete is similar to the relationship between flour and cake. While neither cake nor concrete can be made without the "flour" they are definitely not flour and like a cake, when the concrete has finished "cooking" the flour is nowhere to be seen.

Another way to think about it is that; cement is the glue in the concrete holding the sand and stone together. It should also be noted that like many glues, cement doesn’t dry, it hardens through a process called hydration.

Just as different occasions call for different types of cakes (one would never take Christmas cake to a 2 year old’s birthday party) different applications call for different types of concrete. While basic concrete can be made at home, most concrete today can only be made by your local ready-mixed concrete manufacturer and delivered ready to use in a ready mixed-concrete truck.

There are as many different concrete mixes as there are applications for concrete, and the design mixture used for a parking ramp will differ radically from the mix used for a basement floor. Furthermore, the material and procedures used to construct a concrete driveway in a warm climate, like Southern California, are completely different from the requirements necessary to construct a durable driveway, pool deck, walkway or basement floor in a more severe climate, such as the Lower Mainland. Freeze and thaw cycles, coupled with exposure to chemical de-icers can cause the wrong mix of concrete to crack, shrink or scale.

Rempel makes different kinds of concrete products using different quantities of aggregates like gravel or crushed stone plus cement, water, air and sand. Rempel buys most of its aggregate and other raw materials from local suppliers and has strong partnerships with many leading construction supply firms in the Lower Mainland and Fraser Valley.

What is fly ash?

Fly ash is a by-product from coal fired electric power generating plants. The inorganic or mineral constituents of the coal, such as clay, quartz and shale, fuse and chemically recombine during burning to produce various crystalline and glassy phases of fly ash. The fly ash is entrained in the flue gas and cools into spherical, usually hollow shaped particles. These particles are collected in electrostatic precipitators or bag houses and the gradation, or fineness, of the fly ash can be controlled by how and where the particles are collected. Fly ash reacts with the free lime generated by cement hydration to form cement-like compounds, which increase the strength and reduce the permeability of concrete.

Why aren’t highways in Canada made of concrete?

It has been estimated that Canada's national highway network requires some $22 billion of investment. Furthermore, this number is increasing because the vicious cycle of maintenance consumes almost all the available money.

Concrete roads will last up to 40 years with minimal upkeep and will reduce fuel consumption and accidents. However, despite their obvious advantages, concrete roads are less common in Canada than in any other industrialized country, largely because our decision-making has emphasized the short term. Failure to account for both initial capital and maintenance costs has placed Canada at a competitive disadvantage that will need to be redressed in the future.

How do I clean concrete?

Click here to find the details of various cleaning methods depending on the material you need to clean up.