How to Do Concrete – Guide to Calculating Concrete – Specifying Concrete – Ordering Concrete – Prior Concrete Pour Check List – Advantages of Pumping Concrete – Do it Yourself Concrete (DIY)
How to order concrete: Now that your planning is complete and your forms are in place, we suggest you review the type and amount of concrete you will need.
Calculating the Amount of Concrete
Specifying Mix Design
Specifying the correct mix for your job is very important. Concrete specifications consist of Strength (PSI), Slump (basically the thickness), Fiber Mesh, Chemical Additives and weather you require a Concrete Pump. 80% of all concrete poured in Florida is 3000 Psi slab mix or 3000 psi pump mix. Other mixes are also available i.e. 3000 Psi – 5000 Psi mixes, Fine Grout, C-476 Cell and Flowable Fill. All mixes are also available using White Portland, please specify when you order. Below we will cover these specifications:
SpecificationsCompressive Strength Compressive strength must be specified at the time of ordering. (ie. 3000 psi, 3500 psi, 4000 psi, 4500 psi and 5000 psi). More psi = more strength and durability. (Also Note: the higher the PSI the shorter the set time will be.) Typically 80% of the slabs in Florida will be 3000 psi. Slump For our tropical environment we recommend a slump of 5-6 inches (+/- 1″). Note: a slump greater than 6″ may prolong the time you have to wait before finishing, particularly in cool weather. It will also increase the tendency for shrinkage cracking. Unless specified all mixes will be delivered at a 5” slump unless it is going to be pumped in that case we recommend a 5” – 6” slump.
Wire Mesh with 2″ Mesh-Ups
- Pumped concrete can be placed in areas that are difficult or impossible to reach by other placement methods. Our pipelines can corner sharply, pass through narrow spaces, travel over or under walls, through doorways etc.
- Pumping often results in a savings in manpower and equipment cost and cycle time.
- Pumping is not limited by weather conditions, (snow, rain, heat) as the concrete is protected during transport to the placement area.
- Pumping can be used when the space available for construction equipment is limited.
- Pumping concrete frees cranes and hoists for other construction operations, such as delivering materials.
- Pumped concrete can be easier to handle because the flow of concrete is directed to the exact spot of placement. (where as cranes and conveyors deposit large piles of concrete that must be moved manually).
- A continuous supply of pumped concrete remains steady and controlled, helping set a steady work pace for the placement crew.
- Pumping concrete allows a contractor to place floor slabs on upper floors before completing the concrete work on lower floors. This provides protection from weather when working on lower floors.
- For large pours, multiple pumps can be set up, allowing several trucks to discharge at the same time.
- Location of the Pour(s) – Because we mix on-site we can pour multiple locations and different mix designs if required.
- Type of pour (i.e Driveway, Sidewalk, Lintel etc.)
- Contact person, Contact cell number
- Required Compressive Strength
- Should we include Concrete Fiber in the mix
- Can we back up to the pour, or do you need a Concrete Pump – Will wheelbarrows be used?
- Is there a washout area?
- Sub grade must be compacted and moist but, 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 8 – 9 cubic yards 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 able to support up to 80,000 lbs concrete trucks. Pathway must be at least ten (10) feet wide and fourteen (14) feet high Avoid bringing trucks over curbs, sidewalks, or driveways.
- Move any vehicles that may be in the way, or that may get splattered with concrete.
- 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.
- 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 cut as square as possible.
- The control joint depth should be at least ¼ the thickness of the concrete
- Avoid creating triangles or odd shaped panels when placing control joints Have all tools out and ready to go
- Have water hose ready
- Pick up any debris around the work area that my become trip hazards.
- Make sure to have all imbeds ready to go, (i.e. Truss straps if you are pouring a lintel)
- If require have a washout area ready
- Never hurts to have plastic ready in case of bad weather.
- If you are pouring next to something that may get splattered with concrete (ie Sliding glass door), cover it with plastic prior to the pour. One less thing you have to worry about.
- Have drinking water available for your crew
- If curing compounds are to be used have them ready to go
- Have a cell phone on-site so you can keep in touch with concrete dispatcher