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CLEVA-Crete usage information for

builders

Is CLEVA-Crete suitable for undercroft or underground carparks, cellars and lift wells?

Whether in-situ poured, precast or sprayed in, CLEVA-Crete enhanced concrete is incredibly good at keeping any groundwater out.

It will take hundreds of years for moisture with a solid hydrostatic pressure to get through CLEVA-Crete 842 W-P’s defence shield.

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How does CLEVA-Crete stop slab curl?

Slab curl is caused when the concrete has capillaries and moisture is moving in and out of it, just like a sponge, affected by any abutting surface temperatures and moisture levels.

If the substrate under a building or a road or a warehouse is wet, but it is dry on the top or inside, that slab will curl.

CLEVA-Crete doesn’t let any capillaries form.

What price should we allow for using CLEVA-Crete on a project?

CLEVA-Crete has only one wholesale price and is only sold to all the major concrete suppliers.

As a fully-warranted product, on-site quality control is imperative and dosage is by computer either during the batching process, or on-site as requested, protecting you and your client.

As all states price differently, CLEVA-Crete does not set the price in stone, it’s best to contact your concrete suppliers direct to find out the exact price per cube.

CLEVA-Crete’s RRP for:

CLEVA-Crete 842 is $40 per cubic metre (Resolves moisture vapour egress)
CLEVA-Crete 842-WP is $80 cubic metre (Waterproofing to stop ingress/egress)
CLEVA-Crete 842-RP is $110 cubic metre (corrosion inhibitor plus waterproofing)

What are the payment terms?

Payment terms are 30 days from the date of invoice.

How soon after pouring can installation of rubber backed carpet tiles or resilient vinyl occur?

Once concrete has turned from the original plastic stage and has fully set - usually 72 hours - there will little or no moisture egress.

Because CLEVA-Crete technology stops any capillaries from forming, it will not let out any moisture after the original tricalcium silicate hydrate stage sets in the matrix.

It will take the same time as normal concrete to cure, but all moisture will stop in 72 hours, meaning that you can lay all flooring and coating systems as soon as the top surface has reached the pH level of about 8.0 (as required by all the glues and bonding materials specifications).

This usually takes 10-14 days, depending on exposure for carbonation.

Fans may be used for jobs required to be finished 10 to 14 days after the concrete has been poured. Remove all large objects off floor areas and avoid gas heated air movement devices as these create some noxious gases in the air that slow down the process.

In hot and windy weather, does the concrete need to be kept wet to stop plastic shrinkage cracking?

Because CLEVA-Crete stops any capillaries from forming it typically doesn’t crack on top or shrink anywhere near as much as other concrete, but as there will be tension on the very top surface when drying quickly.

On a warm day there will be a lot less surface tension if it is kept wet in such conditions.

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Do CLEVA-Crete’s waterproofing abilities prevent bonding of glues and adhesives for roofing and coating systems or membranes?

Not at all. In fact the opposite occurs.

There have been many examples of bond testing boards snapping when being lifted off by hydraulic jacks, so CLEVA-Crete enhanced concrete is an exceptional material for bonding.

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Is there anything in this material that an environmentally conscious construction business should be concerned about?

There is nothing in CLEVA-Crete or in the process of manufacturing, handling or dealing with it that is at all carcinogenic, toxic, poisonous or hydrocarbon rich.

Instead, it is VOC-free and ideal for ISO14001 certified companies.

How do engineers respond to CLEVA-Crete in the mix design?

CLEVA-Crete provides a superior finish, increased MPa, less shrinkage, lower heat of hydration, controlling ASR, slab curl and dusting.

These attributes provide project specific durability and longevity - factors that are important to most engineers, and they are embracing this global technology.

Engineers know that hydrophobic type water-proofers like caltite work very well, but they also realise that their hydrophobicity causes additional problems in that it slows down or delays effective hydration of the cementitious materials in the concrete, so generally concrete strengths are compromised in some cases up to 35% less compressive strengths, requiring more cement (and cost) to compensate for this.

As crystal growth technologies are reactive, they only work after moisture has come into the concrete and reacted with the crystals.

Engineers also know that once moisture comes into the capillaries of the concrete matrix, that you immediately you start off your process of lowering the pH around the steel, leading to eventual catastrophic failure.

What are your delivery arrangements?

We bulk deliver to batch plants daily.

To ensure a next day delivery the office or your rep in your state must have your purchase order by noon, the day before.

Do you deal with builders direct or just with batch plants?

Our business model is to work directly with the concrete companies and their batch plants so that we can provide the very best quantified construction material through your primary nominated concrete supplier.

However, please don’t hesitate to contact us directly for more information or to answer any questions.

How does CLEVA-Crete affect the setting and curing time of the concrete?

CLEVA-Crete creates and adds more of the right type of calcium silicate hydrate, as it decreases setting times by 13 to 17% on average. It is typical to see 7 to 10 day strengths after 24 to 72 hours from being poured. After approximately 72 hours, there should be no moisture released out of the slab. Full curing time of the concrete usually occurs at the same time as normal, at or soon after 28 days, as with any other concrete or control mixes. At this point there is typically no more than 4 to 11% increase overall after 28 days.

The densifying process of the surface hardness is dependent on weather conditions and humidity. In recent testing, after 28 days of a taber-rotary-abraser test, CLEVA-Crete showed to be a little softer than control, however this all changed after 90 and 120 days. Using the same taber-rotary-abraser test, CLEVA-Crete showed a lot harder and denser than control and all other densifying products tested.

Because of this many engineers are signing off for early stripping, typically four days earlier per each floor.

With good planning, this may bring each project forward based on how many levels in the building and your capacity of your trades to keep up with the concrete pours plus, if vinyl layers can be screeding levels and putting down floors typically after day 14, this also brings a project forward.

On projects in the US using this technology, 20 storey project finishing times have been brought forward by 9-11 weeks.

Do concrete finishers have to use aliphatic alcohol or other types of curing agents?

All CLEVA-Crete admixtures are not the same as an AS 3799—1998. liquid membrane-forming curing compounds.

When an AS 3799—1998. liquid membrane-forming curing compound is specified for concrete, CLEVA-Crete would recommend that you use one. Combinations of high temperatures, winds and low humidity would require placement planning that include ‘Hot Weather’ considerations with concrete placement and finishing.

Whilst in optimal weather circumstances the answer to this question may be no, we recommend all standard procedures for pouring in cold weather and for pouring in hot windy weather as advised by Cement Concrete & Aggregates Australia, should be adhered to. This means that many concrete finishers will choose to use a curing agent, or simply keep the top surface wet till sundown at such times. In normal temperatures and when it’s not a windy day CLEVA-Crete doesn’t normally require any kind of curing agent on top because it cures the concrete from the inside out, and if it’s not a 35° day with high and low RH, it fares very well.

As far as densifiers, CLEVA-Crete is one of the best densifiers available. As it creates masses of nano sized particles of a very pure amorphous style calcium silicate hydrate gel it goes very hard after about two months, so these are not normally required.

How old is the technology and when was it first used in Australia?

CLEVA-Crete technology is thousands of years old.

It was re-visited 100 years ago for the Hoover Dam project by the American Army Corps of Engineers.

They used it in a powder form, which worked very well for them however, with modern batch plants, we have found that this technology in a dry powder form competes for the water at the batching process, so CLEVA-Crete was formulated in a liquid.

This can go in with the head water or it can go in last, just prior to being utilised on site.

This technology has been used in Australia for over eight years now, on projects including large scale warehouses, aquariums, hospitals, aged care facilities, levee banks, many schools, day care facilities and high-end residential buildings.

Does CLEVA-Crete challenge concrete finishers in any way?

All concrete finishers will find that it is slightly different to what they are used to with several benefits.

First of all, it pumps a lot easier than normal concrete with the same slump as the gel created makes it good to handle.

It also lowers the pressure in all pump lines by around 35 to 40%, which makes it easier to pump long distances and up a number of storeys.

Secondly, it also grabs all the excess bleed water and turns it into a gel, so there is no excess bleeding to wait around for, meaning less labour time on the squeegee, wiping the bleed water off of the slab.

Finally, because it starts curing from the inside out, it will increase set times by about 13- 17%. This allows concreters to start finishing with helicopters about an hour earlier on the flatter, level areas, saving around one or two hours on the job.

This is a huge benefit, especially in winter where, with most other technologies, the setting and drawing out of finishing times are often delayed by hours.

When putting a concrete roof on top of a building, how soon can bonding materials and sealers be used?

It is fine to seal up any time after the top surface has reached a pH of around eight (typically, 10-14 days).

Anything will bond extremely well to CLEVA-Crete enhanced concrete.

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Why does CLEVA-Crete require an approved mix design?

The mix design is different for each building and application and the dosage rate varies accordingly.

Also critical is water to cement ratios and how much cementitious material is utilised so, in the early stages of this process, we require that the builder take care of the necessary paperwork so there is no discrepancy.

As the only water-proofer that provides a 25 year warranty and with our $30 million product liability insurance, we know you will be happy with the end result.

Do concrete finishers have to use aliphatic alcohol or other types of curing agents?

CLEVA-Crete admixtures are not the same as an AS 3799—1998, liquid membrane-forming curing compounds.

When an AS 3799—1998. liquid membrane-forming curing compound is specified for concrete, CLEVA-Crete would recommend that you use one.

A combinations of high temperatures, winds and low humidity would require placement planning that include ‘hot weather’ considerations with concrete placement and finishing.

Whilst in optimal weather circumstances, the answer to this question may be no, we recommend all standard procedures for pouring in cold weather and for pouring in hot windy weather as advised by Cement Concrete & Aggregates Australia, should be adhered to.

This means that many concrete finishers will choose to use a curing agent or simply keep the top surface wet till sundown at such times.

In normal temperatures and when it’s not a windy day, CLEVA-Crete doesn’t normally require any kind of curing agent on top because it cures the concrete from the inside out. If it’s not a 35° day with high and low relative humidity, it fares very well.

Is CLEVA-Crete added at the batch plant or on site? Will you be required on-site?

Ideally CLEVA-Crete will go into the mix with the head water at the batch plant, using a special delivery diaphragm type pump that talks directly to the batching computer, removing all opportunity of human error from dosing on site.

Having said that, on a lot of small projects CLEVA-Crete is put in the concrete agitator onsite, with one of the CLEVA-Crete dosing vans or trucks.

These will dose the agitator five minutes before they reverse up to the pump.

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Want to know more? Send an email to info@clevacrete.com.au

Call us on 1300 503 929

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