Concrete finishing is part science, part art. Professional concrete finishers possess skills they have perfected over years of hands on experience. For those that like to do the work themselves, we have developed this Do-It-Yourself guide to concrete. This page contains a list of concrete definitions and tips for concrete preparation, placement, finishing, curing and ordering concrete.

Do It Yourself Index: Site Preparation, Placement, Finishing, Curing

Definitions:

Accelerator - Chemical substance added to a concrete mix that reduces the set time by increasing the rate of hydration.

Aggregate - Concrete is a mixture of water, portland cement, and aggregates (sand and/or stone). Sand is considered a fine aggregate, while any stones are coarse aggregates.

Air Entrained - microscopic air bubbles intentionally incorporated in concrete during mixing to

increase durability and resistance against damage by repeat freeze-thaw cycles. Recommended for all exterior concrete.

Bleeding - The emergence of water from newly placed concrete caused by the settlement of solid materials within the concrete.

Bull Float - a tool comprising a large, flat, rectangular piece of wood, aluminum, or magnesium usually 8 inches wide and 48 inches long and a handle 4 to 16 feet in length used to smooth unformed surfaces or freshly placed concrete.

Cubic Yard - Unit of measure for ready mix concrete. Concrete is ordered, sold, and batched by volume.

Curing - The maintenance of the proper moisture and temperature of concrete in its early stages so that desired properties may develop.

Gravel Mix - A concrete mix that utilizes either pea gravel or larger smooth gravel as its coarse aggregate. This mix is typical for exposed aggregate finishes.

1" Gravel or Native Stone 3/8" Pea Gravel

Grout - A mixture of cement water and sand. No coarse aggregates (stone) is added to grout.

Limestone Mix - A concrete mix that utilizes a crushed limestone aggregate. This mix is typical for most applications where exposing the aggregate is not desired.

1" Crushed Limetone

Performance Mix - Specified at the time of ordering in lieu of sack content. This mix is specified to meet a minimum compressive strength requirement (ie. 3000 psi, 3500 psi, 4000 psi). More psi = more strength and durability.

Portland Cement - A hydraulic cement that sets and hardens by chemical interaction with water.

Ready Mixed Concrete - Concrete purchased and delivered in a plastic and unhardened state.

Sack - A quantity of Portland Cement. One sack weighs 94 pounds.

Sack Mix - The amount of sacks of cement in a cubic yard of concrete. Specified when ordering, concrete is typically referred to as 5 sack mix (or 5.5 sack, 6 sack, etc.) The sacks on cement needed in a mix are usually specified in either the plans or the specifications of a project. More sacks = more strength.

Screeding - The operation of forming a surface by the use of a screed or strike-off and screed guides (typically, the forms).

Set Time - A measurement in hours and minutes of the hardening of concrete to resist a measure of penetration.

Slump - a measure of consistency of freshly mixed concrete, measured in inches. It is the distance that freshly mixed concrete subsides when a conical mold (slump cone) is lifted from the test specimen. Increasing the slump is typically done by increasing the batch water. This method also will begin to erode the strength of the concrete if the slump is raised higher than its designed level.

Sub Grade - The prepared and compacted soil made to support a structure or pavement system.

Water Reducer - A chemical admixture that lowers the amount of mix water needed to achieve a desired slump. The use of a water reducer can help achieve a higher strength as well as making the concrete easier to finish.

Volumetric Mixer - A concrete mixer that measures and produces plastic ready mix concrete by volume rather than weight. Volumetric mixers meter their concrete output as they produce the concrete. Also known as continuous batching.

Do It Yourself Guidelines STEP 1: SITE PREPARATION & PLANNING

Sub grade must be compacted and free of standing water

Forms must be secure and capable of withstanding load pressure of fresh concrete

Arrange enough help to place and finish concrete. Start with a minimum of two (2) people for a 2 cubic yard pour. Add one (1) person for each additional cubic yard of concrete. If you are using wheelbarrows to move the concrete from the truck to the forms, add an additional person.

Assign specific responsibilities to helpers before concrete arrives (I.e. who screeds, bull floats, washes tools, etc.)

Provide acceptable access for delivery:

Pathway must be of stable soil (support of up to 80,000 pounds)

Pathway must be at least ten (10) feet wide and fourteen (14) feet high

Avoid bringing trucks over curbs, sidewalks, or driveways.

The discharge chutes can reach approximately twelve (12) feet

Determine what type of control joints will be used to control cracking; hand tooled or saw cut TIPS:

Concrete used for residential applications should be at least four (4) inches thick

Placement of control joints should be determined in the planning step

Control joints should be placed no more than ten (10) feet apart

Sections should be square or nearly so

The joint depth should be at least ¼ the thickness of the concrete

Avoid creating triangles or odd shaped panels when placing joints

STEP 2: PLACEMENT

Concrete must be discharged as close to final position as possible (eliminate "dragging" concrete long distances)

Concrete must be discharged in a timely manner upon arriving to the job site. If you are using wheelbarrows to move the concrete from the truck to the forms, make sure you have enough help to finish the project in a timely manner.

During the placement process, follow these easy steps:

Strike off or "screed" the concrete to the proper elevation or form height with a wood or magnesium straight edge

Immediately after striking off and before bleed water appears, the concrete must be bull floated and the edges formed with an edger.

After bull floating, no finishing practices must take place until bleed water has completely evaporated.

Concrete will be glossy when bleed water is present and will dull when it evaporates.

STEP 3: FINISHING

Finishing is the process of texturing the concrete. If you are using hand-tooled control joints, these must be completed prior to final texturing. The following textures may be applied:

A broom or brush finish is recommended for exterior applications that require maximum skid resistance such as; sidewalks and driveways. To achieve a broom finish; simply push or pull the concrete broom across the concrete when it reaches the desired consistency; timing is a judgment call based on desired depth of broom texture

A porous trowel finish is recommended for exterior applications that require minimal skid resistance such as; patios and porches. To achieve a porous trowel finish; trowel the concrete when it reaches a consistency that supports your weight but leaves footprints approximately ¼" deep

A hard trowel finish is recommended for interior applications that require a non-porous surface such as shop floors and garage floors. To achieve a hard trowel finish the concrete must be finished with a power trowel.

For decorative or architectural finishes we recommend that you hire a qualified concrete contractor that specialize in decorative concrete.

STEP 4: CURING

Curing is the most important step in concrete placement, yet is typically the most neglected. To ensure that concrete reaches its maximum designed strength and durability, it must be properly cured. This process must begin as soon as the concrete will accept the process without damage to the surface. There are two methods for curing concrete:

Wet Curing is the process of keeping the concrete surface saturated. A garden sprinkler is typically used for this type of curing.

Curing Compound is a chemical that seals in the moisture. They are typically applied with a sprayer but can also be rolled on with a paint roller.

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HOW TO PLACE AN ORDER

Just in case you are wondering what information we will need to provide you with your concrete we've provided a list of needed information. For 31 years we have been providing concrete to homeowners and start up contractors so we have vast experience in helping those new to concrete. We are glad to help you with any questions you may have about your project. Give us a call!

Information Needed

Your name

Date of Delivery

Time of Delivery

Delivery Address or Intersection

Phone Number

Payment Method

In Service Use (driveway, sidewalk, patio, etc)

Quantity in Cubic Yards (we can compute this for you)

Mix Description (sack or performance mix, preferred aggregate)

Source: http://www.custom-crete.com/do_it_yourself.htm