For more than 20 years Evenrange has been successfully manufacturing specialized concrete curing compounds and coatings for the civil and commercial construction industry. Products such as Evencure high grade concrete curing compounds use environmentally responsible formulations and are used in a range of applications from busy highways to car parks and warehouses.

Evencure

Evenrange Evencure liquid impermeable-membrane curing compunds are “apply and forget” systems that effectively, efficiently and economically replace labour intensive curing systems such as wet hessian, polythene or ponded water.

Our vision

Water proof, protect, strengthen and enchance.

FAQ's

Crazing concrete? Curing concrete?

Company overview

For more than 20 years Evenrange has been successfully manufacturing specialized concrete curing compounds and coatings for the civil and commercial construction industry. Evenrange was the FIRST company in Australia to introduce hydrocarbon resin curing compounds to major civil projects.

During the past 20 years Evenrange have strived to formulate products that are safe to use, environmentally friendly and consistently still performs above the requirements set out by Standards and its customers. Some of these products currently being used today include XDS, Evencure BCP, Evencure AC and Evencure W30.

Over the past 10 years Evenrange have undertaken an extensive research program to develop and manufacture unique concrete enhancement and repair materials as a result of a comprehensive market investigation, research and development, lengthy testing and trials.

Primarily the company’s goal was to establish and develop products that were environmentally and user friendly, exhibit high performance in harsh working environments and above all be 100% compatible with concrete.

With new environmentally friendly technology we have forged new industry alliances and with our research facilities and testing laboratories we now offer our clients technical expertise and custom blended materials for any project requirements.

Environmental statement

Since its inception in 1990 Evenrange has maintained itself as an industry leader with its high quality industry approved products that maintain a strong environmental emphasis. From product design to our manufacturing practices Evenrange has always found that maximising an environmentally friendly approach makes both good social and business sense.

The future of industry is in partnership with the environment

We believe and promote the following principles:


  • We will comply with all applicable federal, state and local environmental laws and regulations.
  • We will encourage our suppliers to follow good environmental and sustainable practices. We will give preference to certified suppliers.
  • We will actively seek to introduce new environmentally friendly products to meet market demands.
  • We will stay abreast of developments and issues of environmental importance.
  • We will financially support reasonable environmental initiatives and training.
  • We will integrate environmental considerations into business planning and decision making processes.

We shall conduct our business with the highest applicable legal and ethical standards and shall strive to contribute to economic development and environmental protection. We want our associates to have a work environment where they feel safe and secure. To that end, we shall:

  • Comply with all applicable environmental, health and safety laws
  • Establish environmental health and safety management systems based on recognized standards, and a set of company-wide goals and objectives for continual improvement.
  • Integrate environmental, health and safety considerations into all key business decisions – including the design, production, distribution and support of our products and services.
  • Ensure our products are safe, and work with suppliers and customers to promote responsible use throughout their lifecycle.
  • Strive to reduce environmental impact and conserve natural resources by minimizing waste and emissions, reusing and recycling materials, and responsibly managing energy use.
  • Encourage and educate our associates to take personal accountability for protecting the environment and creating a safe and healthy workplace.

Meeting these objectives is a primary management goal and the individual and collective responsibility of all Evenrange.


The future of industry is in partnership with the environment

FAQ's

Read more about the what’s, why’s and how’s?

1. WHAT is Plastic Shrinkage Cracking?


Plastic shrinkage cracks are cracks that appear on the surface of a freshly placed concrete slab during the finishing operation or soon after. These cracks are usually parallel to each other on the order of 1 to 3 feet apart and 1 to 2 inches deep rarely do they intersect the perimeter of the slab. Plastic shrinkage cracks rarely impair the strength of concrete floors and pavements. Nevertheless they are unsightly. The development of these cracks can be minimised if appropriate measures are taken prior to and during construction.


Note: Plastic shrinkage cracks should be distinguished from other early or pre-hardening cracks caused by settlement of the concrete on either side of a reinforcing bar due to bleeding and resistance to settlement over the bar of because of formwork movement.


2. WHY Do Plastic Shrinkage Cracks Occur?


The most common explanation for the occurrence of plastic shrinkage cracking is that the rate of evaporation of surface moisture exceeds the rate at which it is being replaced by bleed water. This causes shrinkage of the surface while the underlying plastic concrete remains the same volume. However, some field investigations have shown that the bleeding characteristics of concrete do not have a major influence on plastic shrinkage cracking. There is evidence that all cement paste shrinks during early hydration, which produces very small micro cracks. When the rate of evaporation is high and the concrete has enough strength (or stiffness) to cause horizontal shrinkage the normal micro cracking tendency is accentuated and noticeable plastic cracking may result. Following are examples of weather conditions, which increase the rate of evaporation and therefore, the risk of plastic shrinkage cracking.


a. Decrease in relative humidity. Changes in relative humidity have pronounced effects on the rate of evaporation. If the relative humidity changes from 90% to 50% the rate of evaporation is increased by five times.

b. Increase in wind velocity. When wind blows across the surface of concrete during placement and finishing the evaporation of surface moisture will increase. For example an increase in wind speed from 0 to 10mph will quadruple rate of evaporation.

c. Temperature. If the temperature of both the concrete and the surrounding air rises the rate of evaporation will increase. For instance when the temperature of both concrete and air increases from 50 to 70 degrees Fahrenheit the rate of evaporation of water from the surface can double.

d. Rapid evaporation and plastic cracking may also occur when the temperature of the concrete is significantly higher than the air temperature (and the “dew point” temperature). This can occur in cold weather with heated concrete even when the humidity is high and the concrete is placed indoors where the wind velocity is negligible.


3. HOW to Minimise Plastic Shrinkage Cracks


Attempts to eliminate plastic shrinkage cracking by increasing the bleeding characteristics of the concrete either by increasing slump or by using different cement or aggregate of by addition of a retarder have not been found to be consistently effective. To reduce plastic shrinkage cracking it is important to recognize ahead of time, before placement. When weather conditions may occur that are conducive to plastic shrinkage cracking.


Precautions can then be taken to minimise it occurrence. They are:

a. Have proper manpower. Equipment and supplies on hand so that the concrete can be placed and finished promptly. If delays occur cover the concrete with wet burlap, polythene sheeting or building paper between finishing operation. Some contractors find that plastic shrinkage cracks can be prevented in hot dry climates by spraying a chlorinated rubber-curing compound or monomolecular film on the surface behind the screeding operation and before floating or screeding.

b. Start curing with liquid membrane curing compound as soon as bleed water has gone and the new concrete has hardened sufficiently so as not to be marked by the application process.

c. If concrete is to be placed on a dry subgrade or on previously placed concrete, the subgrade or the concrete base should be thoroughly dampened. The formwork and the reinforcement should also be dampened.

d. The use of vapour barrier under a slab on grade greatly increases the risk of plastic shrinkage cracking. If a vapour carrier is required cover it with a 2-inch layer of damp sand.

e. In the very hot and dry periods use fog sprays. Erect temporary windbreaks to reduce the wind velocity over the surface of the concrete and if possible also provide sunshades to control the surface temperature of the slab. If conditions are critical schedule placement to begin in the late afternoon or early evening.


Follow These Rules to Minimise Plastic Shrinkage


1. Dampen the subgrades and forms.
2. Prevent excessive surface moisture evaporation by providing fog sprays and erecting windbreaks
3. Cover concrete with wet burlap or polythene sheets between finishing operations.
4. Use cooler concrete in hot weather and avoid overheating the concrete in cold weather.
5. Cure properly as soon as finishing has been completed.


EVENRANGE liquid impermeable-membrane curing compounds are “apply and forget” systems that effectively, efficiently and economically replace labour intensive curing systems such as wet hessian, polythene or ponded water. These latter systems whilst effective if utilised properly, require constant maintenance because they are very easily disrupted by atmospheric conditions such as winds or high temperatures.


EVENRANGE can supply the curing compound most suited to your needs whether it be water based, solvent based, bituminous and chlorinated rubber.


References:
1. ACI Standard Recommended Practice for Hot Weather Concreting ACI 305. ACI Manual of Concrete Practice. Part 1.
2. “Report on Behaviour of Concrete in Hot Climate’ by R. Shalon RILEM No. 62, March-April 1978.
3. “Plastic Shrinkage” by W. Lerch. ACI Journal. February, 1957.
4. “Control of Rapid Drying of Fresh Concrete by Evaporation Control” by W.A. Cordon and J.D. Thorpe. ACI Journal 1965.
5. “Prevention of Plastic Cracking in Concrete” Concrete Information #ST80. Portland Cement Association.
6. “Cracking of Fresh Concrete as Related to Reinforcement” by P.D. Caddy. ACI Journal. August. 1975.


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  1. WHAT is Crazing?

Crazing is the development of a network of fine random cracks or fissures on the surface of concrete or mortar caused by shrinkage of the surface laver. These cracks are rarely more the 1/2 inch deep and arc more noticeable on steel-trowelled surfaces. The irregular hexagonal areas enclosed by the cracks are typically no more than 11/2 inches across and may be as small and Y to 3/8 inch in unusual instances. Generally, craze cracks develop at an early age and are apparent the day after placement or at least by the end of the first week. Often they are not readily visible until the surface has been wetted and it is beginning to dry out. Crazing cracks are sometimes referred to as shallow map or pattern cracking. They do not affect the structural integrity of concrete and rarely do they affect durability of wear resistance. However, crazed surfaces can be unsightly. They are particularly conspicuous and unsightly on concrete, which contains calcium chloride.


WHY Do Concrete Surfaces Craze?


Concrete surface crazing usually occurs because one or more the rules of “good concrete practice” were not followed.


The most frequent violations are:


  1. Poor or inadequate curing. Intermittent wet curing and drying or even the delayed application of curing will permit rapid drying of the surface and provoke crazing.
    b. Too wet a mix, excessive floating, the use of a jitterbug or any other procedures, which will depress the coarse aggregate and produce an excessive concentration of cement paste and fines at the surface.
    c. Finishing while there is bleed water on the surface or the use of steel trowel at a time when the smooth surface of the trowel brings up too much water and cement fines. Use of a bull float or darby while bleed water is on the surface will produce a high water-cement ratio weak surface layer which will be susceptible to crazing, dusting and other defects.
    d. Sprinkling cement on the surface to dry up the bleed water is a frequent cause of crazing surfaces. This concentrates fines on the surface.
    e. Occasionally carbonation of the surface causes crazing. Carbonation is a chemical reaction between cement and carbon dioxide or carbon monoxide from unvented heaters. In such instances the surface will be soft and will dust as well.

  1. HOW to Prevent Crazing

To prevent crazing start curing the concrete as soon as possible. The surface should be kept wet by either flooding the surface with water, covering the surface with damp burlap and keeping it continuously moist for a minimum of 3 days or spraying the surface with a liquid membrane-curing compound. Curing retains the moisture required for proper combination of cement with water. This chemical reaction between cement and water is called hydration.


  1. Use moderate slump (± to 5 inches) of air-entrained concrete. Higher slump (up to 6 or 7 inches) can be used providing the mixture is designed to produce the required strength without excessive bleeding and/or segregation. Air entrainment helps to reduce the rate of bleeding of fresh concrete and thereby reduces the chance of crazing.
    c. NEVER sprinkle or trowel dry cement or a mixture of cement and fine sand into the surface of the plastic concrete to absorb bleed water. Remove bleed water by dragging a garden hose across the surface. DO NOT perform any finishing operation while bleed water is present on the surface.
    d. Dampen the subgrade prior to concrete placement to prevent it absorbing too much water from the concrete. If an impervious membrane such as polythene is required on the subgrade cover it with 1 to 2 inches of damp sand to reduce bleeding.

Follow These Rules to Prevent Crazing


  1. Use moderate slump (3-5 inch) air entrained concrete.
    2. Finish properly.
  2. Remove bleed water before performing any finishing operations. DO NOT dust any cement onto the surface to absorb

bleed water.
b. Avoid excessive manipulation of the surface, which can depress the aggregate, increase the cement paste at the surface and increase the water-cement at the surface.
c. Delay steel trowelling until water sheen has disappeared from the surface.

  1. Cure properly as soon as finishing has been completed.

EVENRANGE liquid impermeable-membrane curing compounds are “apply and forget” systems that effectively, efficiently and economically replace labour intensive curing systems such as wet hessian, polythene or ponded water. These latter systems whilst effective if utilised properly, require constant maintenance because they are very easily disrupted by atmospheric conditions such as winds or high temperatures.


EVENRANGE can supply the curing compound most suited to your needs whether it be water based, solvent based, bituminous and chlorinated rubber.


References:
1. “Recommended Practice for Concrete Floor and Slab Construction” ACI 302, Manual of Concrete Practice, Part 1.
2. “Slab Construction Practices Compares by Wear Tests” by L. Blake Fentress, ACI Journal, July 1973.
3. “How to Prevent Concrete Slab Surface Defects Portland Cement Association (IS777.01).
4. “Solutions to the Problems of Scaling, Crazing. Dusting of Concrete Slabs” Modern Concrete, November 1963.


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  1. WHAT is Scaling?

When concrete scales from freezing and thawing the finished surface flakes or peels off. Generally it starts as localized small patches, which later may merge and extend to expose large areas. Light scaling does not expose the coarse aggregate. Moderate scaling exposes the aggregate and may involve loss of up to 1/8 to 3/8 inch of the surface mortar. In severe scaling more surface has been lost and the aggregate is clearly exposed and stands out. (Note: Occasionally concrete peels or scales in the absence of freezing and thawing). This type of scaling is not covered in this article. Often this is due to the early use of a steel trowel or finishing while bleed water is on the surface.


  1. WHY Do Concrete Surfaces Scale?

Concrete slabs exposed to freezing and thawing in the presence of moisture and/or de-icing salts are susceptible to scaling.


Most scaling is caused by:


  1. The used of non-entrained concrete or too little entrained air. Adequate air entrainment is necessary for protection against freezing and thawing damage. However, even air-entrained concrete will scale if other precautions are not observed.
    b. Application of calcium or sodium chloride de-icing salts. If other salts such as ammonium sulfate or ammonium nitrate are used they can cause scaling as well as inducing severe chemical attack of the concrete surface.
    c. Any finishing operation performed while bleed water is on the surface. If bleed water is worked back into the top 1/4 inch of the slab a very high water-cement ratio and, therefore, a low strength top surface layer is produced.
    d. Insufficient or no curing. This omission often results in a weak surface skin, which will scale if it is exposed to freezing and thawing in the presence of moisture and de-icing salts.

  1. HOW to Prevent Scaling

  1. To prevent scaling the use of air-entrained concrete is a must. Severe exposures require air contents of 6 to 7 percent in freshly mixed concrete made with 3/4 inch or 1-inch aggregate. In moderate exposures where deicing salts will not be used 4 to 6 percent air will be sufficient. Air-entrained concrete having a low water-cement ratio and moderate slump (up to 5 inches) helps produce a strong wear resistant surface.
  2. DO NOT use de-icing salts such as calcium or sodium chloride, on new or recently placed concrete. Use clean sand for traction. Never use ammonium sulphate or ammonium nitrate as a deicier, these are chemically aggressive and destroy concrete surfaces. Poor drainage, which permits water or salt and water to stand on the surface for extended periods of time greatly increase the severity of the exposure and causes scaling. (This is often noticed in gutters and sidewalks where the snow from ploughing keeps the surface wet for long periods of time). Light applications of salts can be more damaging than heavy applications: even salts carried on cars may cause severe scaling of newly placed driveways.
  3. Provide proper curing by using liquid membrane curing compound. Curing insures proper combination of cement with water known as hydration, which allows the concrete to achieve its highest potential strength.
  4. DO NOT perform any finishing operations with water present on the surface. Initial screeding must be promptly followed by buffloating.
  5. Protect concrete from the harsh winter environment. It is important to protect the young concrete from becoming saturated with water prior to freeze and thaw cycles of the winter months. Seal the surface with 50150 mixture of boiled linseed oil and mineral spirits. The concrete should be reasonably dry prior to the application of a sealer. Late summer is the ideal time for surface treatment. The sealer can be sprayed on or brushed on the surface of the concrete. CAUTION: Linseed oil will darken the colour of the concrete and care should be taken to apply it uniformly.

  1. HOW To Repair Scaled Surfaces

The repaired surface will only be as strong as the base surface to which it is bonded. Therefore the surface to be repaired should be free of dirt, oil or paint and most importantly it must be sound. To accomplish this use a hammer and chisel.


Sandblasting or jackhammer to remove all weak or unsound material. The clean rough, textured surface is then ready for a thin bonded resurfacing such as:
a. Portland cement concrete resurfacing
b. Latex modified concrete resurfacing

Follow These Rules to Prevent Scaling


  1. For moderate to severe exposures, use air-entrained concrete of medium slump 3-5 inches
    b. Cure properly
    c. If late winter placement cannot be avoided in moderate to severe climates do not use de-icers for first winter and seal surface with boiled linseed oil
    d. Use correct timing for all finishing operations
    e. Select the proper mix to match placing conditions. Specify air-entrained concrete.
  2. Use an accelerator and lower slump in cold weather.

EVENRANGE liquid impermeable-membrane curing compounds are “apply and forget” systems, that effectively. Efficiently and economically replace labour intensive curing systems such as wet hessian. polythene or ponded water. These latter systems, whilst effective if utilised properly require constant maintenance because they are very easily disrupted by atmospheric conditions such as winds or high temperatures.


EVENRANGE can supply the curing compound most suited to your needs whether it be water based, solvent based, bituminous and chlorinated rubber.


References:
1. “Durability of Concrete in Service” ACI 201. Chapter2. ACI Manual of Concrete Practice Part1
2. “Scaled Concrete” by Fred F. Bartel. Tews Lime and Cement Company
3. “Problems of Ice Removal from Pavements” by William E. Dickinson. Calcium Chloride Institute. NRMCA Pub. No. 98 “Protective Coatings to Prevent Deterioration of Concrete by De-icing Chemicals” National Cooperative Highway Research Program Report N. 16
5. “Recommended Practice for Concrete Floor and Slab Construction” ACI 302. Manual of Concrete Practice. Part 1.
6. “The Effect of Various Surface Treatments using Zinc and Magnesium Fluorosilicate Crystals on Abrasion Resistance of Concrete Surfaces” Concrete Laboratory. Report No. C 819. U.S. Bureau of Reclamation
7. “An Unusual Case of Surface Deterioration on a Concrete Bridge Deck” by John Ryell ACI Journal. April. 1965


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1. WHAT is Dusting?


Chalking or powdering at the surface of a concrete slab is called dusting.
The characteristics of such surfaces are:


a. They powder under any kind of traffic
b. They can be easily scratched with a nail or even by sweeping


2. WHY Do Concrete Floors Dust?


A concrete floor dusts under traffic because the wearing surface is weak.
This weakness can be caused by:


a. Any finishing operation performed while bleed water is on the surface. Working this bleed water back into the top 1/4 inch of the slab produces a very high water cement ratio and, therefore. a low strength surface layer.
b. Placement over a non-absorptive subgrade or polythene. This reduces normal absorption by the subgrade, increases bleeding and as a result the risk of surface dusting.
c. Insufficient or no curing. This omission often results in a soft surface skin, which will easily dust under foot traffic.
d. Floating and/or trowelling of condensation moisture from warm humid air on cold concrete. In cold weather the concrete sets slowly, in particular cold concrete in basement floors. If the humidity is relatively high water will condense on the freshly placed concrete, which, if trowelled into the surface, will cause dusting.
e. Inadequate ventilation in close quarters. Carbon dioxide from open salamanders, gasoline engines or generator, power buggies or mixer engines may cause a chemical reaction known as carbonation which greatly reduces the strength and hardness of the concrete surface.
f. Inadequate protection of freshly placed concrete from rain, snow or drying winds.


3. HOW to Prevent Dusting


a. In general, use concrete with a moderate slump (not over 5 inches). However, concrete with a higher slump (up to G or 7 inches) may be used providing the mixture is designed to produce the required strength without excessive bleeding and/or segregation. The higher slump levels can be used in hot weather when setting time is reduced and less time is available for bleeding. In cold weather delayed setting will increase bleeding and require use of lower slump. Concrete having a low water cement ratio and moderate slump helps produce a strong wear resistant surface.
b. NEVER sprinkle or trowel dry cement into the surface of plastic concrete to absorb bleed water. Remove bleed water by dragging a garden hose across the surface. Excessive bleeding of concrete can be reduced by using air-entrained concrete by modifying mix proportions and by reducing setting time.
c. DO NOT perform any finishing operation with water present on the surface. Bleed water can be worked into surface fines from delayed bullfloating. Initial screeding must be promptly followed by bullfloating.
d. Avoid direct placement of concrete on polythene or nonabsorptive subgrades. Place 1 to 2 inches of damp sand over polythene or non-absorptive subgrade prior to concrete placement. On absorptive subgrades dampen the surface just prior to concrete placement.
e. Provide proper curing by using liquid membrane curing compound. Protect young concrete from the environment.
f. When placing concrete in cold weather use warm concrete as well as an accelerator.


4. HOW to Repair Dusting

a. To minimize or eliminate dusting, apply a chemical floor hardener such as zinc or magnesium fluorosilicate in compliance with manufacturers directions on thoroughly dried concrete. If dusting persists, use hardeners with cementitious properties of their own, such as latex formulations, boiled linseed oil or paint.
b. In severe cases a serviceable floor can be obtained by wet grinding the top surface, followed by properly bonded placement of a topping course. If this is not practical, installation of a floor covering such as carpeting or vinyl tile covering is the least expensive solution to severe dusting.


Follow These Rules to Prevent Dusting


a. Use moderate slump concrete
b. Finish properly
c. Cure properly


EVENRANGE liquid impermeable-membrane curing compounds are “apply and forget” systems that effectively, efficiently and economically replace labor intensive curing systems such as wet hessian, polythene or ponded water. These latter systems whilst effective if utilised properly require constant maintenance because they are very easily disrupted by atmospheric conditions such as winds or high temperatures.
EVENRANGE can supply the curing compound most suited to your needs whether it is water based, solvent based, bituminous and chlorinated rubber.


References.

1. “Job Conditions Affect Cracking and Strength of Concrete in Place” by Richard H Campbell ACI Journal. January 1976
2. “Recommended Practice for Concrete Floor and Slab Construction” ACI 302-69
3. “Causes of Floor Failures’ by AT. Hersey. ACI Journal June 1973
4. “Slab Construction Practices Compared by Wear Test” by Blake Fentress. ACI Journal July 1973
5. “Cement Masons Manual for Residential Construction’ Portland Cement Association
6. “The Effect of Various Surface Treatments using Zinc and Magnesium Fluorosilicate Crystals on Abrasion Resistance of Concrete Surfaces” Concrete Laboratory Report No. C 819. U.S. Bureau of Reclamation
7. “Concrete in Practice National” CIP 1 by Ready Mixed Concrete Association


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  1. WHAT is Curing?

Curing has a strong influence on properties of hardened concrete such as durability strength, watertightness, wear resistance, volume stability and resistance to freezing and thawing.


When Portland cement is mixed with water, a chemical reaction called hydration takes place. The extent to which this reaction is completed determines the strength. durability and density of the concrete. Most fresh concrete contains considerable more than enough water for completed hydration of the cement; however any appreciable loss of water by evaporation or otherwise will delay or prevent completed hydration. Since hydration is relatively rapid the first few days after fresh concrete is placed, it is important for the water to be retained during this period, that is, for evaporation to he prevented or at least reduced.


  1. WHY Cure Concrete?

The objects of curing are:


  • To prevent (or replenish) the loss of moisture
  • To control the concrete temperature for a definite time

With proper curing, the concrete will become stronger and more resistant to stress, abrasion and frost. The improvement is rapid at early ages but continues more slowly for an indefinite period. When moist curing is interrupted, the development of strength continues for a short period and then topes. However, is moist curing is resumed, strength development will be reactivated. Although it can be done in a laboratory it is difficult to resaturate concrete in the field. Thus, it is best to moist-cure the concrete continuously for the time it is placed until it has sufficient strength, impermeability and resistance to abrasion, freezing and thawing and chemical attack.


Loss of water will also cause the concrete to shrink, thus creating tensile stresses at the drying surface. If these stresses develop before the concrete has attained adequate tensile strength. surface cracking can result. All exposed surfaces, including exposed edges and joints, must be protected against moisture evaporation. Hydration proceeds at a much slower rate when the concrete temperature is low. Temperatures below 10°C are unfavourable for the development of early strength; below 4.5°C the development of early strength is greatly retarded; and at or below freezing temperature, down to -10°C. little or no strength develops. In recent years, a maturity concept has been introduced to evaluate the development of strength when there is variation in the curing temperature of the concrete. “Maturity” is defined as the product of the age of the concrete and it’s average curing temperature. It follows that concrete should be protected so that it’s temperature is kept favourable for hydration and moisture is not lost during the early hardening period.


  1. HOW to Cure Concrete.
  2. PONDING
    – Build dike, then fill with water to cover the entire concrete slab
    – Avoid water or dike material that can stain the concrete
    – Use curing water at temperature within 20°F of the concrete temperature.
    – Avoid premature of sudden release of ponded water, which can damage the surrounding environment
  3. SPRINKLING OR FOG SPRAYING
    – Keep surface continuously wet alternate wetting and drying cause craze cracking
    – Use low water pressure and flow to avoid washing away the fresh concrete surface
    – Use a water temperature within 20°F of the concrete temperature
    – Avoid if water runoff can damage the surrounding environment
  4. USING WET MATERIALS
    – Cover the concrete with wet hessian, straw, sawdust or sand
    – Wet continuously or cover plastic sheets and wet frequently
    – Avoid materials that discolour concrete
    – Prevent materials from blowing away
  5. USING PLASTIC SHEETS OR WATERPROOF PAPER
    – Use flat. lap edges 6 inches. and cover exposed concrete edges
    – Use minimum 4 mil thick plastic sheet: white in hot weather and black in cold weather
    – Don’t use on architectural concrete
    – Secure covering to prevent concrete exposure
  6. USING CURING COMPOUNDS
    – Apply to the concrete as soon as the bleed water has gone and the new concrete has hardened sufficiently so as not to be marked by the application process.

References.

  1. “Design and Control of Concrete Mixtures. EB001.12T. Chapter 10. Portland Cement Association. 1980
    2. Readymix (W.I.) Limited

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1. WHAT are Blisters?


Blisters are hollow, low-profile bumps on the concrete surface typically from the size of a $2 coin up to an inch, but occasionally even 2 or 3 inches in diameter. A dense trowelled skin of mortar about 1/8 inch thick covers an underlying void which moves around under the surface during trowelling.


The void forms under a dense surface skin by one of two phenomenon. Some believe that incidental air voids rise in sticky concretes and are trapped under a dense surface skin produced by trowelling. Other believe that bleed water rises and collects for form a void under this skin. That water is reabsorbed into the underlying concrete leaving a layer of irregular void space under the surface which is then consolidated by trowelling to form a round blister which moves during subsequent trowelling. Frequently, the blister is lined with a faint layer of “washed” sand.
In poorly lit areas, small blisters may be difficult to sec during finishing and may not be detected until they break under traffic.


2. WHY Do Blisters Form?


Blisters form when the fresh concrete surface is sealed by trowelling while the underlying concrete is plastic and bleeding or able to release air. The small round blisters form fairly late in the finishing process, after floating and after the first trowelling. Moderately rapid evaporation of bleed water makes the surface ready to be trowelled while the underlying concrete is still bleeding or still plastic and releasing air. Evaporation from the surface is increased by wind. low relative humidity or a warm concrete surface. If evaporation is too rapid. the slab will be affected to a depth of an inch or more and blisters will be prevent – but plastic shrinkage cracks may develop! Entrained air is often involved since it reduces that rate of bleeding and supplies the fat necessary to produce the dense impermeable surface layer. A cool subgrade will delay set in the bottom and make the top set first.


Blisters are more likely to form if:
a. The subgrade is cool and the concrete in the bottom sets slowly.
b. Entrained air is used or is higher than normal so that the surface is ready to finish earlier.
c. A dry shake is used. particularly over air entrained concrete.
d. The concrete is sticky from higher cement content or excessive fine sand. Lean mixes bleed rapidly for a shorter period. have higher total bleeding and tend to delay finishing.
e. The slab is thick.
f.  The slab in on polythene and the slump is less than 3 or 4 inches.
g. Excessive use of a jitterbug or a vibrating screed which works up a thick mortar layer on top


3. How to Prevent Blisters


The finisher should be wary of a concrete surface that appears to be ready to trowel before it would normally be expected to be. Emphasis in finishing should be on placing, straightening and floating the concrete as rapidly as possible and without working up an excessive layer of fat. After these operations are completed, further finishing should be delayed as long as possible and the surface covered with polythene or otherwise protected from evaporation. In initial floating the float blades should be flat to avoid densifing the surface too early. Use of an accelerator or heated concrete often prevents blisters in cool weather.


If blisters are forming, try to either flatten the trowel blades or tear the surface with a wood float and delay finishing as long as possible. Any steps that can be taken to slow evaporation should help.


Follow These Rules to Avoid Blisters


1. Do not seal surface before air or bleed water from below have escaped.
2. Avoid dry shakes on air-entrained concrete.
3. Use heated or accelerated concrete to promote even setting throughout the depth of the slab.
4. Do not place slabs directly on polythene sheeting.


References.


1. “Guide for Concrete Floor and Slab Construction” ACI 302 1R-8C, Sections 2.4.1, 8.4 and 11.7 Concrete International. June 1980 pp. 51-96 and ACI Manual of Concrete Practice, Pan 2, 1983. American Concrete Institute.
2. “Carl O. Peterson “Concrete Surface Blistering – Causes and Cures” Concrete Construction Publications, September 1970
3. “Finishing” Concrete Construction, August 1976 p. 369
4. “J.C. Yeager. “Finishing Problems and Surface Defects in Flatwork. Concrete Construction, April 1979
5. Problems and Practices. ACI Journal. December 1955


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Products

Evencure

Evenrange Evencure liquid impermeable-membrane curing compounds are “apply and forget” systems that effectively, efficiently and economically replace labour intensive curing systems such as wet hessian, polythene or ponded water. These latter systems whilst effective if utilised properly, require constant maintenance because they are very easily disrupted by atmospheric conditions such as winds or high temperatures. Evenrange can supply the curing compound most suited to your needs whether it be water based, solvent based, bituminous and chlorinated rubber.

XDS – Water Based Emulsion

Evencure XDS is a blend of resins and surfactants in water and is specially formulated to cure freshly laid concrete.


Tech data MSDS Boral Cert. Boral Graph.

W30 – Wax Based Emulsion

Evencure W30 is a wax based sprayable curing compound formulated to cure freshly laid concrete. It is a low-med viscosity white pigmented emulsion of specially blended waxes.


Tech data MSDS Boral Cert. Boral Graph.

AC – Acrylic Modified Emulsion

Evencure AC is an acrylic mod emulsion used as a curing membrane on freshly poured concrete.


Tech data MSDS Boral Cert.

BCP – Bituminous Hydrocarbon

Evencure BCP is a blend of bitumen & hydrocarbon resins emulsified in water, preventing excessive water evaporation.


Tech data MSDS Boral Cert. Boral Graph.

Eco-Cure

Eco-Cure™ is an environmental liquid membrane compound manufactured for use on concrete Road and Highway Construction.Eco-Cure™ is the first of its kind and a unique curing compound that does not contain Hydrocarbons like Resins and Mineral Spirits.Eco-Cure™ has been proven to have better performance than the traditional Hydrocarbon based curing compounds.


MSDS

AA – Aliphatic Alcohol

Evencure AA is a low viscosity blend in an aqueous solution. Evenrange AA is applied to freshly placed concrete surfaces, to reduce water evaporation during the critical “finishing” period of the concrete, particularly under adverse weather conditions such as high temperature, high winds and low humidity.

Files coming soon.

H

Files coming soon.

X-Pose Concrete Surface Retarder

Evenrange X-Pose Concrete Surface Retarder is a uniquely formulated liquid that retards the surface of the concrete, whilst allowing the subsurface to still harden. This unique feature allows easy removal of the treated concrete while the subsurface concrete remains hard and limits the failure of the aggregate bond in the exposed concrete.


Tech data MSDS

BCP – Bituminous Hydrocarbon

Evencure BCP is a blend of bitumen & hydrocarbon resins emulsified in water, preventing excessive water evaporation.


Tech data MSDS Boral Cert. Boral Graph.

Evencure Ezispray

Evencure EP Ezispray is a fine particle, high solids, modified CRS 170 bitumen emulsion. Due to it’s unique formulation Evencure EP Ezispray can be applied through standard spray equipment including gear pumps and once dried is a trafficable coating.


Tech data MSDS

EC-20 – Asphalt Emulsion

EC-20’s membrane forming technology, allows the product to cure, seal, and form a bond in stabilized bases.

Files coming soon.

EC-30 – Asphalt Emulsion

EC-30 is designed to penetrate ½ to 1 inches into the base and sub-base of stabilized limestone, gravel and caliche bases.

Files coming soon.

DS – Dust Suppression Soil Stabilization

Dust management is a critically important part of road saftey. Evenrange DS is produced from Molassperse CA and it is based on a natural organic compound that proves an ideal product for dust suppression.


Tech data MSDS

Stripcure

STRIPCURE 12P is a specially formulated stripper for hydrocarbon based curing compounds that are slow in oxidising or have been applied to the concrete surface too heavy creating irregular patters and high film build up.


Tech data MSDS

Contact

Address

12 Frankston Gardens Drive,
Carrum Downs,
Victoria, 3201, Australia.

Contact

+61 3 9782 3233 (B.Hours)
+61 417 346 280
+61 3 9782 3244
steve@evenrange.com.au
www.evenrange.com.au