FREQUENTLY ASKED QUESTIONS

According to the Portland Cement Association, although the terms cement and concrete often are 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 stone; the paste is water and portland cement. Concrete gets stronger as it gets older. Portland cement is not a brand name, but the generic term for the type of cement used in virtually all concrete, just as stainless is a type of steel and sterling a type of silver. Cement comprises from 10 to 15 percent of the concrete mix, by volume. Through a process called hydration, the cement and water harden and bind the aggregates into a rock-like mass. This hardening process continues for years, meaning that concrete gets stronger as it gets older.

Curing is one of the most important steps in concrete construction, because proper curing greatly increases concrete strength and durability. Concrete hardens as a result of hydration, the chemical reaction between cement and water. However, hydration occurs only if water is available and if the concrete's temperature stays within a suitable range. During the curing period (5-7 days after placement for conventional concrete) the concrete surface needs to be kept moist to permit the hydration process. New concrete can be kept wet with soaking hoses, sprinklers, or by covering it with wet burlap. Alternately, it can be coated with commercially available curing compounds which seal in moisture.

Concrete, like all other materials, will change in volume slightly when it dries. In typical concrete this change amounts to about 500 millionths. Translated into dimensions, this is about 1/16 of an inch in 10 feet (0.4 cm in 3 meters). The reason contractors put 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.

(Source: Portland Cement Association) 

Air-Entraining Admixture (AEA) generates an air-void system for increased protection for exterior concrete against damage from freezing, thawing, or severe weather.

Type A Water Reducing Admixtures (WRA)

Type A water reducing admixtures are added to concrete to reduce the water-cement ratio or to improve the workability of concrete without changing the water-cement ratio. Water reducers typically decrease water content by 5 to 10 percent.

Mid-Range Water Reducing Admixtures (MRWRA)

Mid-range water reducing admixtures can be used in a variety of concrete mixtures because of dosage flexibility. Particularly suited for flatwork applications, mid-range water reducers contain ingredients that improve finishability without significantly affecting the time of setting. With up to 20 percent water reduction possible, this multi-purpose product can be a real benefit to your project.

High-Range Water Reducing Admixtures (HRWRA)

Also known as superplasticizer, high-range water reducers provide flowing concrete with slumps of 8 inches and higher. Concrete with very low water-cementitious ratios can be made while maintaining workability, minimizing bleed water, and controlling segregation. Most engineering qualities of concrete are enhanced by reducing water up to 40 percent. Normal doses of high-range water reducer can help save time and money through improved production and reduced labor. Use high-range water reducer anywhere increased plasticity is desired.

Corrosion Inhibitors

Two different products are available to help protect reinforcing steel by reducing the rate at which chloride and moisture enter the concrete: Product A and Product B. These additives can extend the service life of reinforced concrete structures. Parking garages, bridge decks, or other applications requiring corrosion protection can benefit from the use of corrosion inhibitors.

Shrinkage Reducing Admixture (SRA)

Shrinkage reducing admixtures are specifically developed to reduce drying shrinkage and the potential for subsequent cracking. When concrete mixtures with SRA are drying, shrinkage-cracking and micro-cracking are reduced and water tightness and durability are improved, as well as aesthetics.

Mineral Admixtures

Mineral Admixtures in finely divided forms are added to supplement or as a partial replacement of the cement in concrete. These products combine with by-products of Portland cement's hydration process and form additional cementitious compounds. Extensive studies of both long- and short- term properties performed on these materials show that they can improve the desirable qualities of concrete.

Fly Ash CFA/FFA

Due to the spherical nature of fly ash, it acts like tiny ball bearings, lubricating the concrete, and thus allowing lower water content for a given slump. All the benefits of less water content such as increased strength, durability, etc., are realized when using fly ash. Segregation, bleeding, and heat from hydration are reduced. Pumping, finishability, and sometimes alkali-aggregate reactivity and sulphate resistance are improved through the use of fly ash. Normal cement replacement is 15 percent to 25 percent.

FIBERS

Synthetic Fibers

Synthetic fiber reinforcement inhibits the formation of plastic shrinkage cracks by providing an internal support system when concrete is most vulnerable to cracking. Literally millions of small polypropylene fibers are integrally mixed, providing reinforcement throughout the entire concrete section. Synthetic fiber provides an alternative to small gauge wire mesh and provides impressive improvements in permeability, impact resistance, and abrasion resistance.

Steel Fibers

Steel fibers can be used to replace rebar in certain applications and because they come premixed in concrete, valuable time can be saved. Steel fiber enhances concrete's flexural and shear strength, impact resistance and ductility. Steel fibers inhibit cracks in concrete, and are often requested for jobs requiring more durability.

Blends

A blend of steel and synthetic fibers may be used to gain the benefits of both.

Color

Pigments may be added to concrete to produce architectural effects. The pigment is added as a percentage of the cement to produce many different colors. For cleaner, brighter colors, pigment can be used with white cement instead of the normal gray variety. Many factors - such as temperature, finishing operations, added water, and curing - affect the final color, so no guarantee of final product can be made; however, with proper care, a beautiful effect can be obtained.

Others

• High density concrete
• Shotcrete
• Pervious concrete
• Polymer modified concrete
• Lightweight concrete
• Exposed Aggregate
• Backfill Material CLSM
• High early strength
• Mass concrete

“Slump” is shorthand for the concrete slump test, which measures the consistency of fresh concrete before it sets. This test checks the workability of freshly made concrete and the ease with which concrete flows. It can also be used to identify an improperly mixed batch.

As it relates to our industry, the word aggregate refers to any combination of sand, gravel, or crushed stone in its natural or processed state.

Technically, gravel is the material mined from a creek or river bed and consists of rounded rocks that have become smooth over many years of rolling together in a stream of water.

However, "gravel" has become a slang term for the material on any rock road, parking lot, or driveway. It is common for a customer to ask us for some "gravel for my driveway," when most likely they probably need a crushed stone product such as Crusher Run.

Every project is different and consideration should be given to the general condition of the construction site, drainage, and use. Some basic "rules of thumb" apply.

While we produce many different sizes of crushed stone, these products can be categorized in two groups. One group is made up of materials that are clean and have little or no "fines" or smaller rock in them. The other group consists of materials that do have smaller particles in them down to and including dust.

Clean rock is what is used to make concrete, chip seal a road, or put in a lateral line.

Materials that include fines are commonly referred to as "base materials" and are best for roads, parking lots, or driveway projects. The fines in the product act as a binder, holding the rock together and making a compacted sturdy base. A clean material lacks that binder and will not compact.

Some specific materials and their most common applications are listed below:

Clean Rock

Base Materials

Sand

The formula for determining the quantity required for your project is as follows:

Length x Width x Depth (in feet) ÷ 27 = Cubic Yards

We then multiply the number of cubic yards by the conversion factor for tons per cubic yard.

An example would go something like this:

"My driveway is 100 feet long and 10 feet wide, and I would like to have 4" of rock on it after it is compacted."

100 feet long x 10 feet wide = 1,000 square feet

1,000 square feet x 4" thick (4" = 0.33 of 1 foot)

1000 x 0.33 = 330 cubic feet

330 cubic feet ÷ 27 cubic feet per cubic yard = 12.2 cubic yards

12.2 cubic yards x 1.8 tons per cubic yard = 22 tons

Following are some "rules of thumb" for figuring quantities:

Thickness

Commonly Used Conversion Factors (tons per cubic yard)

• Screenings, 1 1/2" Crusher Run

1.35 loose weight
1.80 compacted

• Chips, 1 1/2" #57, Coarse Materials, Sand

1.25 loose weight
*Note: This material will not compact significantly

• Fill Sand

1.25 loose weight

• Concrete Sand

1.25 loose weight

Yes, we do. Delivery is our specialty. We pride ourselves on delivering on quality, service, our word – everything we do. But to be specific, we deliver aggregate and ready-mixed concrete. We have ways of delivering concrete to almost any job site, but aggregate is a little different.

We have three methods of delivering aggregate to our customers:

For shipments between 1 ton and 15 tons, our end dump "bobtail" trucks will deliver the material. Bobtail trucks have the ability to maneuver easily in almost every construction site and they can also spread the material out a little bit, traveling as they dump.

For shipments of 25 tons or more, we ship by end-dump semi-trailer trucks. These large 18 wheel trucks haul 25 tons per load. End dump semi-truck delivery requires that the job site has adequate access, a level place to dump, and adequate clearance from trees or high line wires in close proximity. End-dump semi-trailer trucks cannot spread material; they dump the load in one pile.

Even though you need more than 25 tons, your job site may require bobtail truck deliveries because of site or access restrictions. We can check that out for you.

For larger construction projects, we can ship our aggregate materials to you in railroad cars from our facilities. Each railroad car has a capacity of 95 tons.