A: Problem: When water evaporates from concrete the color of concrete bleaches out (becomes lighter). The water to cement ratio in concrete is what dictates color. Concrete patching compounds that conform to ASTM C 928 often have a low water/cement ratio <0,4. Most concrete walls have a water/cement ratio >0.5. Therefore they won’t match, with the patch being much darker.

Problem: If white Portland cement and gray Portland cement are mixed with sand, they will not be cohesive. White Portland demands more sand to cement than gray. Therefore, a packaged gray mixture and a package white mixture that are properly proportioned will mix and are cohesive.

Problem: Match patching requires that both the patch area and the patch material be similar in moisture content. Therefore, if the wall to be patched has dried out, then the patch must be matched dry.

Solution: Recrete 5 is manufactured in both gray and white and are properly proportioned, and can be mixed in any proportion.

Solution: Mix the gray and white in differing proportions, continuously increasing the amount of white. Add these proportioned mixes to the correct water ratio for patching and mix and allow the patches to dry or dry them in a micro-wave-oven. Mix the wall patch in the proportion that is closes to the color of the wall. The tie hole often has form oil in the void and should be de-grease. A bonding admixture such as Ad-Bond (J-40) improves bond, flexural and tensile strengths and improves workability.

A: Problem: Drilling into concrete is relatively slow, and it is a given that some of the cement laitence will adhere to the side-walls of the hole. Therefore, any hole should be mechanically brushed and vacuumed before inserting an epoxy for doweling. Solution: J-50 or J-51 require that a hole in concrete be surface prepared so that the greatest possible surface area is available for bonding. A 1/8” oversized power driven wire brush is ideal, along with vacuuming the grindings, way to prepare a dowel hole for either J-50 or J-51.

A: The carpet and tile mastic manufacturers made an agreement with EPA to remove all solvents from their carpet and resilient tile mastics. They agreed not to manufacture ¡§cut-back¡¨ mastics, which contained solvents. For this agreement, the carpet and resilient tile mastics manufacturers are exempt form the Clean Air Act. The solvents in the old cur-backs softened the acrylic or chlorinated-rubber curing and sealing compounds so that a good bond was achieved and the curing and sealing compound also restricted vapor transmission or served as a vapor barrier. These new mastics will not bond to any organic compound. Therefore, no membrane forming curing compounds, manufactured in the US today, that conform to ASTM C 309 and are compatible with the currently available carpet and resilient tile mastics.„h Solution: Use a silicate as the curing method, such as Sil-cure (J-13), and delete the need for conform to ASTM C 309. This method is effective if the application is indoors out of any wind.

A: In 6.6.1. in ASTM C 1315 requires that carpet and resilient tile mastics bond to curing and sealing compounds. This is impossible; since the mastics on the market today, are water based and will not bond to curing and sealing compounds. „h Solution: recommend that only area that will not receive carpet and tile be treated with a curing and sealing compound that complies with the other paragraphs of ASTM C 1315, Day-Chem Cure & Seal (J-23) complies with the other requirements of Class A.„h Solution: ASTM C 309 is a moisture retention specification. ASTM C 1315 incorporates: moisture retention, yellowing, chemical resistance and mastic compatibility.

A: Plastic shrinkage occurs when the rate of evaporation of the surface water in the concrete exceeds the available moisture in the concrete. Plastic shrinkage cracks are more common in periods of low humidity and hot weather.„h Solution: Use an evaporation reducer such as Sure-Film (J-74) right after striking off and straight-edging (bull-floating) of the concrete surface.„h Solution: Curing must commence as soon as the concrete is finished as long as there are no water puddles. Delaying curing can produce more defects than just plastic shrinkage cracking.

A: Checking is the result of accelerated drying in small modules at the concrete surface. It can and often is the result of over working the concrete surface. „h Solution: Outside concrete should not be steel trowelled, and an application of curing compound as soon as the concrete is finished will reduce the potential, but will not cure the problem if the surface were over worked. Use Rez-Cure (J-11-W).„h Solution: Checking is not a structural problem it is aesthetic.

A: Different construction materials: concrete, block and brick have highly variable surface densities. Therefore, the ability of a material to penetrate also varies.„X Solution: Use a siloxane J-26-WB or J-27-WB on porous surfaces and silanes J-29 and J-29-A on dense surfaces.

A: All dissipating resins are hydrophobic. They must be applied to a moist surface to spread out and form a membrane. If applied to a dry surface, they will penetrate and not produce a membrane.Solution: Day-Chem Rez-Cure J-11-W is a dissipating resin, and, if it is applied to a moist surface, and if concrete surface is in direct sun-light, the J-11-W will start breaking down in 30 days. Complete dissipation will take longer and the timing is weather dependent.

A: Silanes when applied to dry concrete produce a monomerization reaction, or they produce a plastic-like film just below the surface of the concrete. Silane was developed in Canada to prevent salting form deteriorating concrete pavements. The Canadians did not want this product to change the profile of the concrete surface (they didn’t want the highway to be slippery).Solution: Weather-worker S-40 (J-29) produces its water-repellent-film below the concrete surface so that the concrete will not be slippery.

A: The drying oils (linseed oil and tung oil) are natural product and have been in existence for hundreds of years. They also have been government subsidized, and they are by-product and cheap.„X Solution: Water repellents such as the Weatherworker S-40 (J-29) is a penetrating sealer that does not alter the surface profile (is not slippery) and will last for many years. DSC will give up to a 10 warranty on these products. Linseed oil produces a more slippery surface, will discolor and will last less than a year as a water repellent.

A: Water-proofers prevent any vapor or water transmission and must be capable of resisting hydro-static pressure. Damp-proofers prevent any vapor or water transmission, but are not able to resist hydro-static pressures. Water repellents must resist surface wetting.Solution: DAYTON-SUPERIOR CORPORATION has water repellents: J26-WB, J-27-WB, J-29 and J-29-A.

A: Split-faced-block are very porous.Solution: Use Weather-worker J-27-WB. J-27-WB has the largest molecule size and the highest solids content.

A: Problem: Bonding agents that are re-dispersible (re-emmisable) can produce delamination if the patch becomes wet, well after the application, and is followed by freezing and thawing (ACI 548-00).

Solution: Ad-Bond (J-40) is non-re-dispersible and can be used both inside and outside. Superior Concrete Bonder (J-41) is re-dispersible, and should only be used inside. Levelayer Bonding Agent (J-42) is re-dispersible and should only be used inside.

A: Solution: J-58 has a 30 minute gel time and would be applicable for an overhead bonder application. "Solution: J-58 will not loose bond strength if the concrete surface has no standing water, and the J-58 must be scrubbed into the concrete surface when it is wet to assure bond.

A: Ans. ASTM C-881 has 3 performance categories; Type, Grade and Class. Basically, *Types I and II are high modulus epoxies for use in non load-bearing applications; Type III is a low modulus for overlays and patching while types IV and V are high modulus epoxies for use in load bearing applications

There are 3 Grades:

1 = low viscosity

2 = medium viscosity

3 = Non-Sag (Gel)
Basically there are 3 classes

A = use below 40°F

B = 40 – 60°F

C = Over 60°F


Dayton Superior products meet the following ASTM 881 Specs:
Types I, II, IV, V, Grade 3, Classes B&C: J-50, J-51
Types I, II, IV, V, Grade 2, Classes B&C: J-58
Types I, II, IV, V, Grade I, Classes B&C: J-56
Type III, Grade I, Classes B&C = J-57

A: The Sure Level Epoxy (J-57) is a low modulus epoxy that is recommended for any exterior use. Use ±50 lbs. of clean dry quartz/silica sand per 1 gallon of J-52 Epoxy.

A: It is recommended to use a Grade 2 or a medium viscosity material for there is not enough ‘body’ in a low viscosity material for a proper bond. Typically bonding agents are applied at ±80 sf/gallon and a low viscosity material is not suitable for this type of build up.

A: Yes, it is necessary. By mixing each component prior to blending you are more assured that you will have all the ingredients suspension when blending to provide a homogenous mix.

A: NO. The surface must be clean and sound. ACI 503 states “Concrete surfaces to which epoxies are to be applied shall be newly exposed parent concrete free of loose and unsound materials. Prepare surfaces by mechanical abrasion.

A: Yes. ACI 503 states “Evaluate moisture content for concrete determining if moisture will collect at bond lines between old concrete and epoxy adhesive before epoxy had cured. This may be accomplished by taping a 4’ x 4’ polyethylene sheet to concrete surface. If moisture collects on underside of polyethylene sheet before epoxy would cure, then allow concrete to dry sufficiently to prevent the possibility of a moisture barrier between old concrete and new concrete.”

A: Yes. Epoxies are both mass and thermally dependent. The more mass the greater the exotherm (heat) that develops and the higher the temperature the faster it will harden and conversely, the colder the temperature the slower it sets.

A: After mixing the epoxy you can separate it into smaller pails reducing the mass and giving you a little longer ‘pot life’. Preconditioning of the material is very helpful also. Keep the epoxy cool in warmer weather to give you more time before it ‘tacks off’. In colder temperatures keeping the material warm will help to accelerate the set time.

A: The Sure Anchor I (J-51) is a gel (grade 3) epoxy that is excellent for vertical/overhead use. The J-51 meets ASTM C-881 and is ICBO approved.

A: AASHTO is an acronym for American Association of State Highway and Transportation Officials. The AASHTO M-235 Specification is the equivalent to ASTM C-881.

A: No. C-881 requires an epoxy to be less than 2000 centipoise (cps) in viscosity to be considered “low viscosity”. Epoxies with a viscosity greater than 2,000 cps, but less than 10,000 cps, are considered a Grade 2 or a medium viscosity material. Therefore an epoxy with a viscosity of 70 cps, or one of 1999 cps are both considered a ""low viscosity” but one will readily notice the difference.

A: ľ Problem: Epoxies are two component materials with mix ratios, and the colors are also in two components. If the mix ratio is varied slightly by not thoroughly cleaning the individual containers, there will be variations form container to container.ľ Solution: When using an epoxy that will be exposed, each container must be meticulously incorporated into the end use product. Use Poxy-Plus (J-36) from as large a container as possible to be applied within the pot-life to insure color uniformity.

A: ƒæ Problem: Cartridges are filled by machine that fills each side of the cartridge with a set weight of product. This is difficult if not impossible in the field.ƒæ Solution: There are bulk dispensing equipment available throughout the US for different mix ratio epoxies. Dayton¡¦s epoxy products are available in bulk: J-50, J-51, J-56 are available in cartridges. When the static mixer is used with the cartridges, and the first ounce or two is not used, the product is properly proportioned. The static mixer can be discarded, the caps put on both components and the cartridge can be stored and used when the caps are removed and a new static mixer installed.

A: ľ Problem: In any grouting operation, the product must be homogeneous to produce consistent bearing. A lower viscosity epoxy can easily settle. When the aggregate separates from the epoxy resin the grout is not homogeneous.ľ Solution: J-54 should be used as if it were a dry-packed cementitious grout. The formwork needs to be anchored on three sides and the J-54 packed or rammed into place.

A: J-50, J-51, J-54 resin and hardener, J-56, J-57 and J-58 should be mixed for three minutes with a Jiffler mixer

A: Problem: If the fresh concrete is formed and reinforced, the formwork would have to lowered, the epoxy applied, the formwork and reinforcing installed, and all need to be accomplished within the gel time of the epoxy, which are usually 30 minutes.

A: Problem: Neat epoxy coatings produce a very slick surface. Solution: J-57, and Poxy-Plus will accept sand broadcast into them, but either requires a second coat, within 24, after the excess sand has been removed. The objective is to encapsulate the sand to the point where each grain is 50% embedded into the epoxy.

A: Problem: 100% solid epoxies will not freeze, but they are difficult to bring back to a workable temperature in a hurry. Solution: J-50, J-51, J-54, J-56, J-57 and J-58 will not freeze, but J-36 will freeze.

A: Epoxies are diluted with diluents. Solution: DAYTON-SUPERIOR CORPORATION does not recommend diluting epoxies.

A: Blistering can be caused by not mixing until there are no streaking of the components or if the epoxy is not homogenous. Blistering can also result from placing a bonder on concrete in hot weather in direct sunlight. Aggregates absorb heat and can often be at a much higher temperature than the cement paste matrix. The epoxy bonder that is directly over the hot aggregate blisters by exceeding the temperature at which the epoxy, a thermo-setting plastic, sets. Solution: Mix Resi-Bond (J-58) in accordance with the instruction on the Technical Data Sheet or on the container (three minutes with a paddle or Jiffler mixer). Do not apply to concrete in direct sunlight in hot weather.

A: Problem: Epoxies bond in direct proportion to the surface area that is to be bonded. Smooth dowels, reinforcing bars and threaded rods all have different surface areas in the same diameters, and the unit with the greatest surface area bonds the best. Reinforcing has the greatest surface area, threaded rod has greater surface area than smooth dowels. Solution: Use Sure-anchor I (J-51) with reinforcing bars in control joints, use threaded dowels if a coil tie or coil anchor is used and a smooth dowel should be used in a contraction joint, and don’t for get to grease the non-anchored end of the smooth dowel so that it can allow the concrete to move horizontally but not vertically.

A: High modulus epoxies oxidize in ultra-violet light and chalk. Chalking continues to a certain depth and ceases, and is more of an aesthetic conditions rather than a structural consideration. Solution: Use a low modulus epoxy like Sure-Level Epoxy (J-57 when the application is exposed to the weather.

A: Problem: When water mixes with cement, the paste that is formed shrinks. Non-shrink grouts compensate for shrinkage by some form of expansion. Expansion can be in the plastic state, before initial set, it can be between initial set and final set, the aggregates can oxidize to produce expansion, or if gypsum is used, hydration takes place, attaching molecules of water to the calcium sulfate molecule, increasing its mass.

Solution: Do not use non-shrink grouts for patching unless the grouting area can be restrained through formwork or is placed beneath something. Both Sure-Grip High Performance Grout and 1107 Advantage Grout can be easily pumped into a formed area, provided there is both an entry port and an exit port.

Solution: Use patching compounds such as HD-50, Perma Patch, Polyfast, HD-25 or Thin Resurfacer.

A: Problem: When a non-shrink grout is placed in an area that is not restrained by formwork or placed underneath something, the movement created by expansive properties, without restraint, produce cracking. Non-shrink grouts are expansive because when the water and cement mix the mixture shrinks. There are four methods of expansion: 1. Aluminum powder produces hydrogen gas that produces expansion in the plastic state, 2. Shrinkage compensating admixtures or type K cement, 3. Metallic aggregates that oxidize to produce expansion and 4. Gypsum which takes on water molecule which attach themselves to the gypsum molecule in the process call hydration.

Solution: Trim off excess non-shrink grout, in un-restrained areas after initial set. Initial set in both Sure-Grip High Performance Grout and 1107 Advantage Grout is about 3 hours at 70 degrees F.

A: Problem: When a an oxidizing metal such as iron is used as aggregate in a non-shrink grout, the oxidization of the iron will continue until the source of oxygen is eliminated. Placing a cementitious cover is common practice when an iron (ferrous) aggregate is used. The degree of oxidization was measured by establishing a torque limit on the bolts that positioned and leveled the base-plate or anchor a machine.

Solution: Sure-Grip Metallic Grout does not contain a totally oxidizing aggregate such as iron, but contains metals that partially oxidize. Therefore, it does not have to be capped. The metal aggregate used in Sure Grip Metallic Grout oxidize only to a depth of one to two outer molecules at the surface of the metal, similar to but not the patina on copper.

A: Problem: Before the advent of plasticizers, the more fluid the consistency of a grout, the lower its strength. Most engineers wanted the highest possible strength. The Corps of Engineers established four consistencies for grouts, CRD C 621: dry-pack, plastic, flowable and fluid. The consistencies are qualified by test. Dry-pack, plastic and flowable are tested by a drop table. The drop table has an inscribed circle that is 12” in diameter and a 2”x2”x2” cube of grout I placed in the center of the circle. If it fills 40% of the circle it qualifies as dry-pack. If it fills the circle, it qualifies as plastic, and if it flows to 40% greater than the circle it qualifies as flowable. A flow cone is use to test the fluid consistency and the grout needs to flow completely through the cone in 30 seconds to be classified as fluid. The cone is 6” in diameter with a 45 o angle cone and 1” orifice. Grout is filled to the top of the truncation. Dry-packing is difficult when plasticizers are used as the plasticizers lubricate the aggregate and cement particle producing fluidity, even at low water ratios.

Solution: Dayton Superior Corporation produces Sure-Grip Dri-Pak grout for applications requiring a low viscosity consistency, but will not flow. It does not contain plasticizers, but requires restraint that is adequate to withstand the pressure required of dry packing.

Solution: Sure-Grip Utility Grout can also be dry-packed, or used in either a plastic or flowable consistency.

Solution: Sure-Grip High Performance and 1107 Advantage Grouts can be dry packed, with great care, but were designed specifically for use in flowable and fluid consistencies.

A: Problem: Grouting is essentially a repair operation, and the most important component of concrete repair is surface preparation. The second most important component of concrete repair is curing and protection (ACI 546).

Solution: Simply put, concrete repair requires that, the degree of moisture- saturation in the substrate to be equal to the moisture saturation of the repair material or the substrate will draw water out of the grout thus causing it to weaken or fail. Bonding compounds such as Ad-Bond (J-40) decrease the need for full saturation of the substrate.

Solution: Sure-Grip High Performance and 1107 Advantage Grouts require surface preparation: saturation of the substrate, and an open concrete surface to prevent and eliminate aggregate transparencies, or moisten the substrate and apply Ad-Bond (J-40). Both products require curing either with a membrane forming curing compound, meeting ASTM C 309, such as J-11-W or a curing and sealing compound such as J-18 or J-22.

A: Problem: Cementitious products react chemically (hydrate) very slowly at temperatures below 40o F. Cementitious products that contain fly-ash cease to hydrate when the temperature of the material is less than 35o F. When cementitious products hydrate, they generate heat (Exotherm). In cold weather, until a cementitious product begins to generate heat, it needs to be temperature protected. In hot weather, just the opposite is true, hydration accelerates, and the grout is much more susceptible to rapid drying and plastic shrinkage cracking.

Solution: Sure-Grip High Performance and 1107 Advantage Grouts need to be protected when the temperature of the grout is 45o F or below, and when the temperature is above 90 degrees F.

A: Problem: Hydrating grouts generate heat (Exotherm), especially when the placement is deep, 3” or greater in depth. Coarse aggregates absorb heat, adding coarse aggregate to grouts, acts as a heat sink, and decreases the potential for expansion cracking.

Solution: Sure-Grip High Performance and 1107 Advantage Grouts require extension with coarse aggregate (pea gravel) when the depth of the placement exceeds 3” of greater.

A: Problem: Feather-edging is patching without restraint, and is generally differential in depth. Neither situation produces a durable patch. Feather-edging greatly diminishes loading capacity.Solution: Concrete that is trowelled often has aggregate transparencies (voids that have a thin film of cement paste covering a void). Abrading the concrete surface opens up aggregate transparencies, exposing the void. Thin Resurfacer can be applied down to 1/16” deep, but should not be applied to an area that will receive vehicular traffic when applied at this depth.

A: Problem: Polymer modified products, do not bleed because the polymer consumes the mix-water not leaving any for bleeding, and, due to the lack of bleeding, the dry concrete surface is more susceptible to plastic shrinkage cracking, than un-modified materials. Moist curing for 24 hours followed by cessation of the moist curing brings some of the polymer to the surface, producing a membrane that will resist rapid moisture loss due to wind (ACI 548-00).

Solution: Following ACI 548-00 polymer recommendation is the preferred method of curing for all Dayton’s polymer modified repair materials: HD-50, Perma Patch, Polyfast, HD-25 or Thin Resurfacer.

A: Problem: Patching materials that are subjected to vehicular traffic require that the patching area be “let-in” to the concrete (saw cut At right angles to the surface) the perimeter of the patch area and chip out to the depth of the saw cut). Saw cutting often grinds laitances into the surface, so the saw cut surface needs to be abraded to achieve sufficient bonding to prevent cracking at the saw cut.

Solution: HD-50, Perma Patch, Polyfast, HD-25 or Thin Resurfacer perform ideally when proper surface preparation precedes the patch.

A: Problem: When water mixes with cement, the resulting paste shrinks. If the patching material is not shrinkage compensated or if the patch is variable in depth, drying shrinkage cracking will occur. The more consistent the depth of the patching area, the less likely the possibility of cracking. Different depths of cementitious materials: hydrate, cure and shrink at different rates. Therefore, at some point where different depths occur, a crack will form. Also, a crack in the substrate will appear at the same location in the patch.

Solution: HD-50, Perma Patch, Polyfast, HD-25 or Thin Resurfacer are shrinkage compensated, but proper surface preparation, moisture saturation, or the use bonding compounds, are required for long term performance.

A: Problem: Cement based grouts have much lower tensile strength than epoxies, but can be used if the tensile requirements are applicable. Also, Epoxies also have much higher bond strength than cementitious materials, but if the bond strength requirements are in line with the job requirements, then use a cementitious non-shrink grout.

Solution: Sure-Grip High Performance Grout was tested by a Department of Transportation, and a # 6 reinforcing dowel was imbedded into a 2” diameter hole, 4” deep and failed after attaining a direct pull-out of 17,500 lbs.

Solution: Ankertite Cement can also be used for grouting fence post and anchor bolts.

A: Problem: Non-shrink grouts contain admixtures that can produce Saponification (the soap reaction). When a basic material chemically unites and reacts with an organic acid, an inorganic ester is produced. Soaps are inorganic esters. When the speed of mixing is greater than the recommendation of the manufacturer, the soap mixes with the entrapped air, from the mixing, and a soap-foam is produced.

Solution: When using a DAYTON-SUPERIOR CORPORATION grout, mix in a mortar mixer (14—20 rpm) or use a paddle mixer on a low speed drill with no greater than 500 rpm, lower is better.

A: Problem: Gravity affects all cementitious mixtures. Therefore, the lower the specific gravity of a material the more it will migrate to the top. Water has the lowest specific gravity of all the components of non-shrink grouts, and the water will migrate to the top, (bleed). If more water is needed for the consistency desired, than the manufacturer’s recommendation, do not add more water.

Solution: Always follow the water ratios as listed in the Technical Bulletins or on the container of the Dayton Superior Corporation Grouts, Grouts are designed to use only the amount of water required to hydrate. Also, the water required to activate the admixtures in grout are also designed into a Dayton Superior Corporation grout, and does not provide additional water for bleeding and segregation and settlement associated with bleeding. Rheologically, this is process is called stability.

A: Problem: The maximum particle size in a mixture should be no greater in either shape or size than 75% of the orifice size in spray equipment. When the maximum size of aggregate in a cementitious mixture is smaller than 75% of the orifice opening, the material is easily pumped or sprayed, provided the angle of internal resistance allows mobility.

Solution: Seal Coat 1000 is manufactured with 200 sieve sand and Type III cement (325 sieve). The proprietary admixtures in Seal Coat 1000 produce a very workable and sprayable mixture with a reasonable pot life, and will spray easily with all the orifice sizes of hopper guns and low-velocity shotcrete guns on the US market.

A: Problem: Slurry is the more common construction term, and has a higher viscosity than a scrub coat, which is more convenient to apply. Define how you get scrub vs. slurry

Solution: Scrub coats are recommended for: HD-50, Perma Patch, Polyfast, HD-25 or Thin Resurfacer. Scrub coats should be mixed to a consistency of mayonnaise, not coffee cream.

A: Problem: Most redi-mix producers use highly sanded mixtures for concrete flat-work, as they are very easy to work with a float or trowel. Dry-shake hardeners produce a very workable surface when placed on a harsh mixture DEFINE. Sandy mixtures subside (settle) more readily than well-graded or harsh mixtures. Subsidence of a mixture brings the fines to the surface along with water. This situation is even worse: a steel trowel is passed across it or if a water reducer is used. This is more the rule than the exception.

Solution: Quartz Tuff is extremely dependent upon the concrete mixture that it is placed upon. Therefore, DAYTON-SUPERIOR CORPORATION recommends that the mix design be reviewed in advance of concrete placement, and they recommend the mix proportions and aggregate gradations as called out in ACI 302-96 and Technical Bulletin 16.

A: Problem: Gap-graded mixtures have been in use throughout the world for many years. When used they must be placed with a slump that is no greater that 3”, and if more than one gap is present, the slump should be closer to 0.

Solution: Use Emery Tuff with a well graded mixture that complies with ACI 302-96, or place it on concrete with a very low slump. This is not as difficult as it may seem as the Emery Tuff produces good workability on a low slump, gap-graded concrete mix.

A: Problem: Self-desiccation takes place when there is insufficient water in a cementitious mixture to allow the water and cement to form a paste and coat all of the aggregate particles. Problem: Many concrete mixtures will not bleed or produce very little bleed water. There are many hydrophilic materials used in concrete mixtures: fly-ash, air entrainment, water reducers, mid-range water reducers, high-range water reducers. If more than one of these hydrophilic materials is used in a concrete mixture, the hydrophilic materials consume the available mix water, leaving little to nothing for bleeding. Dry-shake hardeners need to “wet-out” from the bottom, by bleeding. If the dry-shake is “wet-out” from the top (blessed), gravity prevents it from “wetting out” downward, and there is not sufficient water for the shake to form a paste and bond to the concrete.

Solution: Use no more than one hydrophilic material in a mixture that is to receive a dry-shake hardener, and apply an evaporation reducers such as Sure-Film (J-74) to prevent the available bleed water from evaporating.

A: Problem: Air entrainment agents are chemically a water surfactant. This means that the air entrainment agent lowers the surface tension of water so that the water and cement mix more easily, similar to soap lowering the surface tension of grease on ones hands. If the air entrainment agent mixes with the dry-shake it greatly inhibits the bond of the shake to the concrete. Also, air entrainment looses its effectiveness for freeze-thaw when the concrete surface is worked repeatedly with a steel trowel, which is usually the case with a dry-shake.

Solution: All DAYTON-SUPERIOR CORPORATION dry-shakes: Emery Tuff, Quartz Tuff and Ferro Tuff will require restriction of air entrainment agents.

A: Problem: If a light reflective dry-shake is applied before the bleed water has arisen if can settle more deeply into the concrete mixture and reduce the intensity of the light-reflective affect. Therefore, a light reflective dry-shake, or any colored or metallic dry-shake should be applied after the bleed water has arisen. This is the recommendation of ACI 302-96.

Solution: Quartz Tuff and Ferro Tuff colors or light reflective recommend that they be applied after initial bleeding. Natural Quartz Tuff and Emery Tuff are applied right after striking off and straight-edging or bull-floating.

A: Problem: Bug-holes are the result of poor mix design and vibration techniques. Pin-holes are the result of excess air-entrainment agents or mixtures of admixtures or over-application of form release agent.

Solution: Smooth Finish and Smooth Coat are designed with very fine aggregates to penetrate into either pin holes or bug holes. Either product should be removed from the concrete surface. They are designed to fill the voids and not produce a film on the concrete surface.

A: In the past, formwork was scheduled in large modules, and a form release agent needed a high viscosity to remain on the formwork, and effective, until the forming module was able to be placed. High viscosity form release agents when longevity was required. However, if concrete is placed against a high-viscosity form release agent, shortly after the application of the form release agent, some of the form release agent can adhere to the concrete, producing a discoloration.„h Solution: Always follow the application recommendations of the manufacturer of the form release agent, or call and ask.„h Solution: High-viscosity form release agent can be removed with hot water and a detergent.„h Solution: Form release agent should be manufactured with virgin-oils, not reprocessed oils. All DAYTON-SUPERIOR CORPORATION Form release agents are manufactured with virgin oils. J-1, J-1-A, J-2, J-2-VOC or J-3-VOC.

A: Bugholes are the result of: High sand/aggregate ratios in the concrete mixture, Low fineness modulus of the fine aggregate, poor consolidation practices, and poorly applied or no application of form release agents.„h Solution: Form release agents have the lowest potential for producing bug-holes. Mix design and consolidation techniques are much more significant. No DAYTON-SUPERIOR CORPORATION Form release agent causes bug-holes: J-1, J-1-A, J-2, J-2-VOC or J-3-VOC.

A: The formwork face sheet must be non-staining when white concrete is used.Solution: Any DAYTON-SUPERIOR CORPORATION form release agent can be used for white concrete provided that the formwork face sheet is non-staining. J-1, J-1-A, J-2, J-2-VOC and J-3-VOC. The application rates must be observed.

A: „h Problem: Osmosis is often the cause of a tilt-up panel sticking to a base slab. Osmosis can be prevented, or highly reduces, if a membrane is formed between the base slab and the panel. The lower the permeability of the membrane, the less likely the possibility of osmosis.Membrane forming curing compounds, when applied to fresh concrete as soon as the concrete is finished, produce concrete that has low permeability, high abrasion resistance and greater durability. The final floor-finish may dictate when a curing compound and a bond breaker are used. Call Dayton for the right combination.

A: Membrane forming bond-breakers were used for many years and conformed to ASTM C 309. The membrane forming bond-breakers are generally dissipating resins. Dissipating resins need to dissipate before the concrete panel surface can accept paint. Because owners were not willing to wait for dissipation to paint their panels, the reactive bond-breakers came on the market.Solution: Use Rich-Tilt “E”.Solution: Use J-18, J-22 or J-23, which meet ASTM C 309 as the cure coat and Sure-Lift J-5 as the bond-breaker.Solution: Use J-22 or J-23 as the cure coat and Sure-Lift J-6 as bond-breaker.

A: Always add the “B” component (Hardener) to the resin, “A” Component, when mixing in bulk.

A: Integrally colored concrete varies with different mix designs, and the number of revolutions of the redi-mix truck. Sandy mixtures accept integral colors less consistently than harsher mixtures, but harsh mixtures are more difficult to finish with hand tools.„h Solution: Explain to owner that there will be color variations and that curing compounds darken the color of concrete.„h Solution: Apply a dissipating resins (J-11-W) to a moist surface, allow it to dissipate, or remove, apply a mild concrete wash-down solution, rinse and apply a sealer (J-25 or J-35) to the surface after it is completely dry.

A: All curing compounds that conform to ASTM C 309, will tire mark. Liquid hardeners that dust-proof and harden do not meet ASTM C 309.Solution: Moist cure followed by Sure-Hard (J-17).Solution: Apply J-11-W, remove with J-48 after 7 days, wait 7 days and apply J-17.

A: The surface density of concrete varies in the finishing process, and lower concrete densities absorb curing compounds, and will appear dull. Higher densities do not absorb but form a film which appear glossy.„h Solution: Always apply any DAYTON-SUPERIOR CORPORATION curing compounds to a moist surface so that a film or membrane is continuous on all surfaces. Use J-18, J-19, J-22 or J-23.„h Solution: If concrete surface is dry, mist water just ahead of the application of the cures above.

A: „h Problem: Aggregates in concrete absorb more heat than cement paste. On the concrete surface above the heated aggregate, the rate of evaporation of a solvent based cure & seal, closest to the aggregate, is much faster than at the top surface of the curing membrane, causing heat stressing of the acrylic solids, which are thermo-plastics and the evaporated solvent produces the blister.„h Solution: Apply at a time of day when the sun is not directly on the concrete surface.„h Solution: Use a water-borne cure & seal such as Day-Chem Safe Cure & Seal (J-18 or J-19)

A: Integrally colored concrete varies with different mix designs, and the number of revolutions of the redi-mix truck. Sandy mixtures accept integral colors less consistently than harsher mixtures, but harsh mixtures are more difficult to finish with hand tools.„h Solution: Explain to owner that there will be color variations and that curing compounds darken the color of concrete.„h Solution: Apply a dissipating resins (J-11-W) to a moist surface, allow it to dissipate, or remove, apply a mild concrete wash-down solution, rinse and apply a sealer (J-25 or J-35) to the surface after it is completely dry.

A: In 6.6.1. in ASTM C 1315 requires that carpet and resilient tile mastics bond to curing and sealing compounds. This is impossible; since the mastics on the market today, are water based and will not bond to curing and sealing compounds. „h Solution: recommend that only area that will not receive carpet and tile be treated with a curing and sealing compound that complies with the other paragraphs of ASTM C 1315, Day-Chem Cure & Seal (J-23) complies with the other requirements of Class A.„h Solution: ASTM C 309 is a moisture retention specification. ASTM C 1315 incorporates: moisture retention, yellowing, chemical resistance and mastic compatibility.

A: Aggregates in concrete absorb more heat than cement paste. On the concrete surface above the heated aggregate, the rate of evaporation of a solvent based cure & seal, closest to the aggregate, is much faster than at the top surface of the curing membrane, causing heat stressing of the acrylic solids, which are thermo-plastics and the evaporated solvent produces the blister.„h Solution: Apply at a time of day when the sun is not directly on the concrete surface.„h Solution: Use a water-borne cure & seal such as Day-Chem Safe Cure & Seal (J-18 or J-19)

A: Many fork-lift’s tires contain carbon-black. When a tire contains carbon-black, and the tire produces a frictional load on a thermo-plastic such as a cure and seal product, the heat stressing produced by this load deposits the carbon-black into the heat-stress cure and seal.Solution: Liquid hardeners such as Sure-Hard (J-17) are completely in-organic, and are not softened, when heat-stressed and little or no carbon-black is deposited. However, quick stops, with high loads can deposit carbon-black on any material.

A: Curing is the control of the moisture level and temperature in fresh concrete. Concrete starts loosing its moisture as soon as it leaves the mixer, therefore, curing should begin as soon as the finishing operation are complete. Any delay can produce carbonization (the absorption of carbon-di-oxide by calcium hydroxide at the concrete surface produces calcium carbonate). Calcium carbonate has extremely low strength. There is recorded evidence of a carbonization layer 1 cm thick, in England, when curing was delayed 3 hours.Solution: Use any Dayton Superior Corporation curing compound: J-9-A, J-10-W, J-11-W, J-18, J-19, J-22 and J-23 as soon as the concrete is finished.

A: ASTM C 309 is the specification that is used for most curing applications. This specification was developed based on the equivalent of a 4 ml polyethylene film (ASTM C 171). To achieve a 4 ml equivalent requires a wet film thickness of a 100% solids material at 400 ft2 per gallon. Solution: Day-Chem Rez-Cure (J-11-W) conforms to ASTM C 309 at 200 ft2 per gallon.

A: Section D of the Clean Air Act has two sections for concrete curing: Concrete Curing Compounds with a maximum VOC content of 350 g/L and Concrete Curing and Sealing Compounds with a minimum of 25% solids and a maximum VOC content of 700 g/L.Solution: Day-Chem Rez Cure (J-11-W) has a VOC content of 313 g/L, and conforms to ASTM C 309.Solution: Day-Chem Cure & Seal (J-23) has a VOC content of 630 g/L, and conforms to the specification ASTM C 1315 for moisture retention, yellowing and chemical resistance.

A: There are many specification that require either Higher solids contents or greater moisture retention. Some of these specification are no longer applicable, there are designers that still use them.Solution: The Dayton Products that comply with ASTM C 309 are: J-9-A, J-10-W, J-11-W, J-18, J-19, J-22 and J-23.Solution: The Dayton Products that comply with ASTM C 1315 is J-23, if the requirement for mastic adhesion is dropped.Solution: The Dayton Products that comply with TT-C-0800 (removed in 1974) are J-18, J-19, J-22 and J-23.Solution; The Dayton Products that comply with CRD C 300 (Removed in 1993, now defers to ASTM C 309) are J-9-A 300 and J-10-W IL comply to the old spec.

A: The viscosity of any liquid increases when the temperature decreases.

A: Water has entered the container or water has been placed on the product. Or, a second coat was applied before the first coat had cured complete, trapping some of the water in the product.

A: At what temperature was the concrete when the product placed? If the concrete is cold the product is a thermo-plastic and is thick when cold and fluid when warm.

A: . J-23 is a membrane forming curing compound or a membrane forming sealer. As a curing compound it must be applied to a moist surface. If applied to a dry surface, it can penetrate. When blotchy, some formed a membrane and some of it penetrated. When you are not sure there is moisture at the surface, a misting of water will allow the entire product to form a film on the moist surface.

A: . Apply a second coat after the first coat is completely cured out. The best way to tell is to get down and smell the product. If any odor of solvent or the odor of latex paint is gone the product is cured. Normally, the first coat is applied to fresh concrete right after finishing has been completed, and the second coat is applied near the completion of the project.

A: The temperature of the concrete, when cold, increases the viscosity. A high viscosity produces a stickiness that does not allow the product to release from a roller. Also the nap of the roller affects the ability of the roller to release, so a short nap roller needs to be used and a lower viscosity should be recommended. Concrete that is below 40o F does not loose its water through evaporation quickly, which is why concrete is cured. Delaying curing is acceptable, if the area where the concrete is placed is not windy. Wind is the most detrimental effect to the hydration of concrete.

A: Solvent based liquids will start to thicken when the temperature of the liquid is 40F, and can become slushy at about (-) 15F, and can freeze solid at (-) 50F.

A: Concrete pavers are designed not absorb water. Therefore, penetrating sealer are not effective. Solution: DAYTON-SUPERIOR CORPORATION membrane sealers are J-35, J-25, J-24 and J-24HD.