MASCO Catalog: Concrete Forming & Accessories

236 MASONS SUPPLY COMPANY Oregon (800) 537-3407 ♦ Washington (800) 537-6216 Clackamas | Eugene | West Eugene | Hillsboro | Medford | Portland | Salem | Ridgefield | Seattle | Tacoma | Woodinville M A S C O . N E T GENERAL & TECH INFO Concrete Volume One cubic yard of concrete (27 ft 3 ) will cover: Concrete Jointing "Concrete cracks. The trick is to get it to crack where you want it to." Joint Types: Contraction Joints – Tooled in or saw cut into slab. Construction Joints – Area where two successive placements of concrete meet. Isolation Joints – Used to effectively isolate a section or area of the slab from other areas of the slab. Joints are designed and implemented into the project as much as the concrete mix is. Properly designed and implemented joints can add years to the service life of the slab. Concrete Setting / Stiffening The chemical process by which concrete hardens and gains strength is called hydration. Hydration time can be altered by as much as 30% for each 10°F change in ambient temperature. Typical concrete placed at 70°F (concrete temperature and ambient temperature) achieves final set in about 6 hours. Concrete and ambient temperatures will affect the setting of the concrete as shown in the table to the right: Concrete Thickness (in) Coverage Area (ft 2 ) 4 81 5 64.8 6 54 7 46 8 40.5 9 36 10 32.4 11 29.5 12 27 CONCRETE TIPS Adding Water "Water is the best / worst thing you can add to your concrete." Adding one gallon of water to one cubic yard of a typical 3000 psi concrete can: • Increase the slump by about one inch • Reduce the compressive strength by about 250 psi • Increase the possibility of passage of moisture throughout the concrete by up to 50% • Increase the shrinkage potential by about 10% Properties also affected water addition: Lessened wear resistance Increased dusting potential Increased cracking potential Reduced durability Temperature ( ° F) Approximate Final Set (hours) 30 19 + 40 14:40 50 10:20 60 8 70 6 80 4 90 2:40 100 1:40