FREQUENTLY ASKED QUESTIONS
What is the difference between cement and concrete?
Although the terms cement and concrete are often used interchangeably, cement is actually an ingredient of concrete. Concrete is basically a mixture of aggregates and paste. The aggregates are sand and gravel or crushed rock. The paste is water and Portland cement. Portland cement is not a brand name, but the generic term for the type of cement used in virtually all concrete. Through a process called hydration, the cement and water harden and bind the aggregates into a rocklike mass. This hardening process continues for years, meaning that concrete gets stronger as it gets older.
Can it be too cold or too hot to pour new concrete?
Temperature extremes make it difficult to properly cure concrete. On hot days too much water is lost by evaporation from newly placed concrete. If the temperature drops too close to freezing, hydration slows to nearly a standstill. Under these conditions, concrete ceases to gain strength and other desirable properties. In general, the temperature of new concrete should not be allowed to fall below 50 degrees Fahrenheit.
Why does concrete crack?
Concrete, like all other materials, will slightly change in volume when it dries out in typical concrete this change amounts to about 500 millionths. Translated into dimensions, this is about 1/16 of an inch in 10 feet. The reason the contractor puts joints in concrete pavements and floors is to allow the concrete to crack in a neat, straight line at the joint when the volume of the concrete changes due to shrinkage.
What is 3000 PSI concrete?
3000 PSI concrete is concrete that is strong enough to carry a compressive stress of 3000 PSI at 28 days. Concrete may be specified at other strengths as well. Conventional concrete has strengths of 6,000 PSI or less. Concrete with strengths between 6,000 and 20,000 PSI is considered high-strength concrete.
Will concrete harden underwater?
Portland cement is a hydraulic cement which means that it sets and hardens due to a chemical reaction with water. Consequently, it will harden underwater.
What is a flowable fill?
A flowable fill is a self-compacting low strength material with a flowable consistency that is used as an economical backfill. It is a self-leveling material.
What is a volumetric mixer?
A volumetric mixer is a batch plant on wheels. All the materials needed to produce concrete are carried in separate compartments and mixed on-site as needed. Thus, the term mobile concrete was born. With volumetric mixers, you only pay for the amount that you use after the minimum requirements are met.
How much concrete will I need?
It is very simple to figure how much concrete you will need for any given area. Let's say that you have a form that is 9 foot by 9 foot 4 inches deep. You would multiply 9 x 9 x 4 = 324 , now divide by 324 and your answer is 1. Which means you need 1 cubic yard. This example will work with any measurements. But remember that for your answer to be correct your measurements must be correct. If you are as much as 1/8 inch off on the depth on a 32 yard pour it would take an extra yard or 33 yards.