Colored Concrete Best Practices
Color-CreteTM is designed to be used in all cementitious materials, producing unlimited color effects. The primary applications are cast-in-place, slab on grade, precast, tilt-up, concrete pavers and roof tiles. Color-CreteTM also can be used in concrete curbing, stucco, cast stone and plaster.
Increte Systems colors are pure synthetic iron oxide pigments, manufactured to the highest standards. They are high strength and uniform in color and exceed ASTM C-979 specifications for integrally colored concrete. Color-CreteTM colors are light-fast, lime-proof and totally weather-proof, providing a permanent color fast solution.
Calcium Chloride is NOT to be added as it can create discoloration as uneven light and dark areas in the finished product. Non-chloride accelerators, including hot water, may be used as acceptable accelerators. Specify Color-CreteTM By name ________________________. As designated at the rate of _____ pounds per 94 Ibs. of cement.
Batching & Mixing Guide
Use a minimum cement content of 470 pounds per cubic yard. Cement substitutes, such as Flyash or slag, should not be used unless Increte is consulted for suggestions. If a cement substitute is used, it must be added to all mixes on the project having the same color. Do not exceed a 5″slump (.45 water to cement ratio). Ideally, when mixing at the plant, load the color with the head water then add the balance of the load. Make sure mixer is not dry. Make sure mixer is empty and no concrete left from previous batch, backspin if necessary. Mix the drum or mixer for a minimum of 75 revolutions at mixing speed and a minimum of 5 minutes. When color is added at the job site, increase mix time to 8 to 12 minutes. Always check concrete for thorough and complete color dispersion before placing. Be sure to use the same mix design and slump (4″) from truck to truck (If higher slump is required it may be obtained by the use of water reducing admixtures). It is important to use the same cement as different cements can have different shades of gray that can affect the color. Watch the slump closely as varying slumps is an indication of varying water to cement ratios and this can affect the final color. Never add Color-CreteTM to an empty drum/mixer.
Job Site Samples
A representative job site sample should be produced for each color and/or mix design. These job site samples should be of adequate size to be representative of the actual job and produced with a minimum of 3 cubic yards or 1/3rd the capacity of the mixer. These sample(s) should be cast using the same aggregates, cement, water to cement ratio and finishing techniques to be used on the job. These samples should also be produced and approved prior to commencing the first pour on site.
Job Site Prep
Concrete should be placed over a properly placed and compacted sub-grade. This sub-grade should be free of mud, standing water and frost. If pouring over inconsistent sub-grades such as wood, plastic, asphalt or existing concrete know that this will affect the evaporation rate and cure time of the concrete which can increase the presence of efflorescence and cause color variation.
Placing Finishing and Curing
Place all color-conditioned concrete on a thoroughly uniform compacted surface. Surface should be lightly dampened (no puddles). Concrete must be placed with consistent slump not exceeding 5″ maximum. Troweling may begin after bleed water evaporates. Concrete should be stiff or plastic before troweling or brooming. Hard or late troweling will cause burns or dark spots. Do not add water or other foreign materials to surface upon finishing or discoloration will occur. For exterior installations, apply rotary, broom or other uniformly textured finish for both appearance and slip resistance. Broom, rotary and rough finishes will usually cure more even-colored than smooth troweled surfaces. Evaporation of water can cause a white hazy film (Efflorescence) on the surface of concrete. Efflorescence is more noticeable on colored concrete surfaces giving the appearance of a chalky or faded look. This effect can be reduced or eliminated by proper curing and protection against water penetration. Efflorescence can be removed with mild acid cleaners formulated to remove efflorescence. Follow manufacturer instructions and always test a small area to insure product will not discolor or etch the surface. When applying curing compounds use only those recommended and approved by Increte Systems. lncrete Systems should be contacted prior to the use of other curing methods. Until it is completely cured, the color of concrete is normally less uniform and sometimes darker than the final color. Allow 28 days for full cure. Do not place any foreign materials such as burlap, water, plastic, wood or paper on surface during the curing process. Contact with foreign materials during curing win cause discoloration. Do no! water cure integrally colored concrete.
Once the surface will support foot traffic, Increte Systems’ CURE-CRETE cure and seals are recommended and may be applied to newest colored architectural…concrete surfaces. These products meet the ASTM Standards C309 andC1315. Do not apply cure and seal products in high heat, direct sunlight or windy conditions. See technical information for the appropriate cure product, limitations, precautions and application specifications.
Variations in cement color, type and brand can all produce variations in the final color. Variations in aggregates, finishes, forming materials and methods as well as curing can all affect the final color. It is very important to keep all materials, operations and techniques as consistent as possible. Calcium Chloride should not be added to any concrete containing Color-Crete TM as it can cause discoloration in the finished product.
Prior to pouring you should cast a jobsite sample. Whenever using new forms, they should be seasoned with a slurry of matching color. Please contact Increte Systems for more information on matching slurries. All holes, plugs, gaps and joints should be patched or filled to prevent water leaking out in these areas. If this is not performed the water to cement ratio in the area near the leaks will change and discolor the surface. If using internal vibrators be careful not to allow the vibrator head to come in contact with reinforcing steel or the face of the form as this can create a dark spot on the surface known as a vibrator burn. If using form liners, be sure to remove any cement paste from previous pours and to clean prior to each pour. When pouring integrally colored concrete always use a non-staining form release agent. To help achieve more color consistency, all forms should be stripped when concrete is of same age.
Integrally colored concrete can be maintained by sweeping. Spills should be cleaned up as they occur. Dirt may be rinsed with clean water. Heavily soiled areas may be scrubbed with water and a stiff bristle brush. For stubborn stains we recommend the use of Increte’s Grease- A-way. For best results use this product as directed on the label or refer to the Technical Data Sheet for Grease- A-way. For the maintenance of large areas, auto scrubbers may be used. To maintain surfaces that have been sealed with one of Increte’s acrylic sealers please refer to the Tech/Datasheets for the particular sealers used.
Custom Colors and Matching Services the Increte Systems color service laboratory is available to provide expert assistance for your color needs. Please contact your representative and indicate mix design along with sample of desired color that is to be produced.