Bay Area Ready-Mix Concrete Delivery Since 1954

Did You Know?

Vibration of fresh concrete is only as good as the man running the vibrator, for instance…

  • Over-vibration can cause honeycomb instead or eliminating it as intended
  • Inadequate vibration is sure to result in honeycomb, particularly with low slump concrete.
  • High slump concrete can not stand as much vibration as low slump: very wet concrete, non at all. 
  • Over-vibration will cause loss of entrained air-as much as 50% loss in 30 seconds.
  • Moving concrete around in the form by using the vibrator will result in sand streaks and rock pockets.
  • Cold joints may result even though each lift is vibrated unless the vibrator penetrates just into the lower lift.
  • Partially set concrete can be revibrated without harm provided the vibrator would enter the concrete of its own weight and restore the concrete to a plastic state.
  • A vibrator setting at a flat angle has little effect, if any, on the concrete immediately below. 

Did You Know?

Proper curing of the concrete is one of the most important steps to be followed in the order to allow the concrete to reach its full potential.

Why curing is so important:

  • Improper curing can cut the designed strength by 50%
  • It will crack less, dust less, by stronger, more durable and have a better wear resistance surface
  • It will have fewer pores where water can enter and freeze
  • It will promote less crazing and spalling of the concrete

Methods of Curing:

  • Membrane Curing Compounds
  • Water Spray (keep slab continuously damp)
  • Waterproof Curing Paper
  • Damp Burlap
  • Plastic Sheets
  • Damp Earth, Straw, Sand & Hay
  • Ponding for 7 days

Cure concrete longer when the temperature is below 70 degrees because concrete strengths develop more slowly at lower temperatures.

Did You Know?

One cubic yard of concrete will cover

Square Feet Inches Thick
93 3.5
81 4.0
72 4.5
64.75 5.0
59 5.5
54 6.0
50 46
46 7.0
43.33 7.5

Did You Know?

That if you add only ONE gallon of water to a yard of properly designed 3000 psi concrete.

  • You increase the slump about one inch
  • You cut the compressive strength by as much as 250 psi
  • You waste the effect of 1/4 bag of cement
  • Your increase the possibility of seepage through the concrete by up to 50%
  • You increase the shrinkage potential about 10-15%
  • You decrease the Freeze-thaw resistance by 20%
  • You lower the quality of concrete in many other ways
    • Less wear resistance
    • Dusting
    • Cracking
    • Repairs
  • You can affect setting times in cold weather (Retard)

Did You Know?

Recommended Joint Spacing

Slab Thickness Less Than 3/4″ Aggregate Larger Than 3/4″ Aggregate
3 Inches 6 foot 8 foot
3.5 Inches 7 foot 9 foot
4 Inches 8 foot 10 foot
5 Inches 10 foot 13 foot

Note: Depth of the control joints in the slab should be 1/4 to 1/3 thickness of the slab.

Did You Know?

Proper curing of color

One of the most important steps in the process of placing color conditioned concrete is the curing process. Curing is defined as the maintaining of  a satisfactory moisture content and temperature in concrete for a definite period of time (preferably 7 days), in order to develop the desired properties (strength, durability, water tightness) in concrete. It will also allow the color to develop to its full potential and be uniform in appearance. If there is no curing done, or if it is done incorrectly, you can be guaranteed that discoloration will arise as well as potential for efflorescence and you will have a call back to the job. 

Did You Know?

Concrete Setting Times

The setting of concrete is a physical-chemical reaction. Generally, this chemical reaction is altered by approximately 1/3 for each 10 degree F change. 

As an example of the relationship between temperature and setting times, concrete, at 70 degrees F sets in about 6 hours. Assuming that both the concrete and ambient temperatures are the same, here’s when you can expect concrete to reach initial set at other temperatures.

Temperature Approximate Setting Time
100 °F 1 – 2/3 hours
90 °F 2 – 2/3 hours
70 °F 4 hours
100 °F 6 hours
60 °F 8 hours
50 °F 10 – 2/3 hours
40 °F 14 – 2/3 hours
30 °F 19 plus hours

Contact Us for information on Retarders and Accelerators

Did You Know?

Joints In Concrete

FACT: Concrete shrinks as it dries – therefore it will crack.

  1. Joints are simple good looking Pre-Planned Cracks
  2. There are two basic joints to remember;
    • Contraction Joints… Tooled or saw cut into slab to direct crack
    • Expansion Joints… These isolate the slab from other structures
  3. Joints should be carefully designed and properly constructed.
  4. For further information, contact us