The most expensive ingredient in concrete is the cement, so minimizing concrete costs means minimizing the amount of cement. That's why mortar is stronger than concrete—by eliminating the coarse aggregate, you increase the specific surface of the aggregate and increase the area of the bonding interface.
An 80# bag of pre-mixed cement, sand and gravel (CONCRETE) is 0.6 cubic foot per the bag. There are 27 cubic feet in a cubic yard. So 27 / 0.6 = 45 80# bags.
Recommended Values of Concrete Slump Tests for Various Purposes:
| No. | Types of concrete | Slump |
|---|
| 1 | Concrete for road construction | 20 to 40 mm |
| 2 | Concrete for tops of curbs, parapets, piers, slabs and wall | 40 to 50 mm |
| 3 | Concrete for canal lining | 70 to 80 mm |
| 4 | Normal RCC work | 80 to 150 mm |
Use $90 per cubic yard as a ballpark figure for concrete prices, but concrete slab cost will vary by region. Also, expect a fee of about $60 per load for delivery from a concrete truck for concrete cost. There could be other fees for such things as Saturday concrete truck delivery and small loads.
A typical concrete slab costs $4 to $8 per square foot with most homeowners spending between $5.35 to $6.17 per square foot, or $113 to $126 per cubic yard for both materials and installation. Your final cost will depend on the slabs size, thickness, and if you any special reinforcement such as wire mesh or rebar.
SAKRETE PSI 6000 can be used to construct slabs, sidewalks, patios, steps, floors and footings.
A six bag mix is a concrete mix that has six bags of portland cement in it. In general, the more bags of cement in a mix, the stronger the mix. Most mixes have 5 to 7 bags of cement. Some concrete contractors (usually the old timers) will order their concrete based on bags rather than psi.
Re: Cost of RMC vs On-Site Mixing
I estimated rmc to be costlier by 5% but if you add value to the time, effort and hassle saved, rmc is definitely cheaper. Also rmc produces consistent concrete mix which is very important.One of the least expensive ways to get concrete is to mix your own. You can buy bags of the mix from a home improvement store. Typically, you only have to add water for it to be ready to pour. Otherwise, you risk getting a weaker concrete once it cures, which could lead to cracks or crumbles within a couple of years.
According to the NRMCA - Ready Mixed Concrete Industry Data Survey, the average cost of concrete in 2016 was $108.22 per cubic yard, or $216.44 for the 2 cubic yards needed for the 10x10 patio project listed above.
The bulk of the work for a new DIY concrete slab is in the excavation and form building. If you have to level a sloped site or bring in a lot of fill, hire an excavator for a day to help prepare the site. Then figure on spending a day building the forms and another pouring the slab.
Cost. Ignoring any maintenance costs, asphalt is generally much cheaper to install than concrete. On average, the cost per square foot for asphalt will run between $2.50 to $4.00. It's not unheard of to have a stained concrete driveway with a smooth finish cost over $15.00 per square foot.
In general, and depending on the type of steel fiber used, it can add between $6 to $10 per cubic yard on top of the ready-mix concrete cost. This cost is based on the assumption that you are using 1.5 pounds per cubic yard of concrete.
Quikrete recommends its Quikrete 5000 concrete mix for driveway use, with coverage of . 6 cubic feet per 80-pound bag. For a driveway foundation 20 feet long, 10 feet wide and 4 inches in depth, the volume of the driveway is 66 cubic feet.
Rent a mixer for big batches
Hand-mixing a few bags of concrete is one thing. Mixing 20 bags will wear you out unnecessarily. Plus, concrete is much stronger if all of it is mixed and poured as quickly as possible.Cost to Install Concrete Patio by Size
| Size in Feet | Square Footage | Price Range |
|---|
| 12x14 | 168 | $1,400-$4,000 |
| 15x15 | 225 | $1,800-$5,500 |
| 16x18 | 288 | $2,300-$7,200 |
| 20x20 | 400 | $3,000-$10,000 |
The difference between cement and concrete
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.Yes, you may pour a concrete pad overlay over an existing slab. You need to consider the added height and weight of the overlay on the existing structure. Overlays may include polymers, portland cement concrete, or epoxies. You should improve the drainage of the slab by having a good slope on the overlay.
How to calculate concrete:
- Determine how thick you want the concrete.
- Measure the length and width that you'd like to cover.
- Multiply the length by the width to determine square footage.
- Convert the thickness from inches to feet.
- Multiply the thickness in feet by the square footage to determine cubic feet.
How to Build a Concrete Patio
- Step 1: Lay Out and Excavate the Patio.
- Step 2: Drive Stakes Along the New Layout Lines.
- Step 3: Nail the First Form in Place.
- Step 4: Splice Boards Together, if Necessary.
- Step 5: Place the Mesh.
- Step 6: Pour the Concrete Into the Forms.
- Step 7: Flatten the Surface.
- Step 8: Round the Edges.
Generally, smaller sheds of up to 8×6 do not need a foundation. Small sheds can be rested on crushed stone with either treated wood foundations or concrete foundation blocks. Large sheds will need to have strong foundations.
The calculator will indicate the number of 60 or 80 pound bags of QUIKRETE® Concrete Mix you need to build a 4″ or a 6″ slab. (All yields are approximate and do not include allowance for uneven subgrade, waste, etc.)
So, there is no such thing as a cement sidewalk, or a cement mixer; the proper terms are concrete sidewalk and concrete mixer. For more information check out the Portland Cement Association.
In general, the aggregate component of a concrete or mortar mix is usually several times that of the cement. For example, a simple sand and cement mix should be at least 3 part sand (the aggregate) to one part cement. A strong concrete mix would be something like 1:3:5 (Cement, Sand, Coarse Gravel).
The typical concrete strength used for a driveway is in the 3000 psi to 4000 psi range, although temperate areas of the country may use lower strengths. Contractors, when ordering ready mixed concrete, should advise the producer of the intended use for the concrete.
The compressive strength of normal concrete has a value ranging between 20 and 40 MPa. The high strength concrete will have strength above 40MPa.
The paper, “202 Observations On Concrete That Is Too-Quickly-Strong,” cites cases where concrete cracked because it was too strong from too much cement and 66 investigations that related durability problems to cement hydrating too rapidly because of high values of fineness, C3S, C3A, and/or alkalies.
Slump. Slump is the measure of concrete consistency and fluidity. It shows the flow and overall workability of freshly mixed concrete. Simply put, the higher the slump, the wetter the mix. Four-inch (4”) slump is very common with normal weight concrete and is a good for pumping.
by thicking up the slab you are creating more resistance to bending by load factors so less cracking. adding more cement increase the psi and its more resistance to bending by load factors, less cracking.
For larger projects such as buildings and homes, the concrete should last 30 to 100 years or more depending on the construction style as well as method of installation. Many times, a concrete shell of a building or home can be reused when the other materials such as wood begin to deteriorate.
The typical concrete strength used for a driveway is in the 3000 psi to 4000 psi range, although temperate areas of the country may use lower strengths. Contractors, when ordering ready mixed concrete, should advise the producer of the intended use for the concrete.
- Use a higher strength mix, like f'c=8,000psi.
- Use Type III Portland Cement in the mix.
- Reduce the water/cement ratio.
- Increase the cement ratio relative to aggregates.
- Use higher temperatures during mixing and curing to accelerate reaction.
- Add Silica Fume or other water reducing ad mixtures.
