Concrete & Concrete Calculations

1. Concrete &Concrete Calculations By: Maddison Black

2. Cement vs. Concrete • Cement: binding material that, when combined with water and aggregate, forms concrete • Concrete: building material formed by combining cement, water, and aggregate

3. Decorative Concrete • Stamped • Stained • Decorative Overlays • Polishing • Decorative Engraving • Stenciling Interior • Exterior Stenciled • Resurfaced • Rock Salt Finish • Scoring & Saw Cutting • Painting

4. Mixing Concrete • Usually comes as a dry mix • Water is added to start a process called hydration • hydration is what causes the concrete to harden not the drying process • Concrete should be consistent all the way through • Fresh concrete should be moist in the first part of hydration http://www.youtube.com/watch?v=mAFTWQM-MdE

6. Forms for Concrete • Forms are typically built above the ground however, some others require digging. • Dig down to the desired level, and build forms to the shape and size needed for the concrete job. • Using temporary posts establish the proper grade or slope of the concrete. • Nail the stakes lightly to the forms used, or clamp the forms temporarily to the stakes with a "C" clamp. • To ensure that you have the proper grade or slope of the concrete form, use a level. • After the proper grade has been set, drive in permanent stakes and nail the form to the stakes.

8. Pouring Concrete • Make sure forms are properly in place. • Spray area lightly with a garden hose, then pour in the concrete. • After the form is filled, compact the concrete by using a tamper, or put on rubber boots and walk around the poured concrete area to make sure it is compacted around the edges.(Small concrete areas can be compacted with a 2x4. For larger areas, rent a tamper.) • Use a straight-edged 2x4 to level the concrete. • Work the 2x4 back and forth in sawing fashion to level the concrete at all points across the form. • In hard-to-reach places use a magnesium concrete rake with an extension handle. • When the concrete has set sufficiently to support a 2x8 plank, use the plank as a straightedge to guide a groover to cut contraction joints. Contraction joints are necessary to allow hardened concrete to expand and contract in extreme temperatures.

9. Calculating Concrete Yardage • Measure the dimensions of the site (length, width, depth) in feet. • Multiply the length, width & depth to obtain the site's volume in cubic feet. • Divide the product by 27 to determine the exact volume in cubic yards. • Multiply this number by 1.05: this gives you 105% of the concrete required. Extra is suggested in case of a spill or accidental waste.

10. Example: Length: 4 feet Width: 2 feet Depth: 8 inches (Picture is not drawn to scale.)

11. Example Continued: 1. Convert 8 inches into feet 2/3 2. 4 x 2 x 2/3 5.3333 3. 5.3333 ÷ 27 .19753 4. .19753 x 1.05 .20741 For a concrete slab measuring 4’ x 2’ x 8”, .20741 cubic yards of concrete is needed.