Precast Suppliers

Frequently Asked Questions

How does CLEVA CRETE affect hollow-core precast elements?

It does two main things when used in hollow-core precast elements or planks; firstly, the gel produced causes the mortar to evenly spread around all the aggregate, so as it passes smoothly through the hollow-core formation machinery, this characteristic causes a smoother concrete and results in decreased noise levels and less wear and tear on the machine.

Secondly, the batchers have noted that when the zero slump mixes for hollow-core planking is being batched, less water is required to get the same slump. This decrease in water required for zero slump mixes in a planetary mixer, results in a stronger MPa every time.

For issues with edge lifter linking rebars not getting the full cover that engineers want, is it possible to minimise the steel cover in areas for concrete elements that will be exposed to extreme acid or alkaline for certain critical infrastructure projects?

Yes, however CLEVA CRETE will always recommend that you take the advice from your engineer over our explanation below.

The answer to this is all very dependent on the size of the aggregate being used in the concrete and whether any steel or synthetic fibres have been used in the matrix, as moisture will travel through absorptive stone and long fibres.

The fact that CLEVA CRETE Modified Concrete (CCMC) makes the mortar extremely impermeable in concrete Precast elements, piers and footings, some stakeholders in the industry are working with 10-12mm cover, especially where edge lifters are involved in structural elements.

In rheology, when using 5 to 7 mm aggregate and no fibres, many involved in cellars, car parks and pools are reducing steel cover.

CLEVA CRETE 842 RP is specifically designed for where you have many low cover areas in precast or if you are pouring deep foundation piles where you know that integrity of steel around perimeter spacers could be compromised while being lowered into position or going into aggressive environments. CLEVA CRETE 842 RP is specifically designed as a Reo Protection product, hence the RP. While such concrete is in its plastic stage there is a chemical reaction that takes place, permanently coating steel with a Rio Protection chemical and thereby doubling the life expectancy of the steel’s integrity.

If CLEVA CRETE has a steep setting curve, what kind of value proposition is it when doing the numbers, given that it is possible to strip and deform much earlier?

CLEVA CRETE increases early setting times by 13 to 17%, sometimes more. It heavily reduces edge chipping and thus saves labour hours patching. It reduces shrinkage, controls plastic shrinkage cracking, reduces heat of hydration, stops slab curl and normal dusting so is an extremely good value proposition in these ways for precast.

When making the decision to use it purely for increased strength and possibly using decks twice in a day to double production, it works out that unless you excessively use steam setting techniques, it does not always enable this.

Is there any benefit to using CLEVA CRETE for smaller precast elements for civil infrastructure?

Many precast companies use CLEVA CRETE with smaller precast elements as you get the shrinkage reduction attributes. Plus, there is no bleed water so labour time is reduced. When used in the manufacture of pipes, you can typically de-mould earlier than normal, with less break-outs.

We use pozzolan admixture to assist in speeding up the setting times. Does CLEVA CRETE modified concrete (CCMC) replace pozzolan admixture?
We already use the best biodegradable and solvent based form release agents, would we need to change these?

CLEVA CRETE creates a concrete that neither egresses moisture or ingresses any liquids or solids, so there is no requirement for your factory to instigate any change to what you are currently using when it comes to release agents used on your form work and decks.

Would you sell CLEVA CRETE direct if we have our own on-site batch plant?

If you do have your own on-site batching facility, you can purchase from CLEVA CRETE direct, exactly the same way as the leading concrete batchers. Contact our office on 1300 503 929.

When doing 2-3 metre thick precast elements, do I need to have the usual sacrificial cooling manifolds throughout the precast sections?

This can only be answered on a case-by-case basis. On a recent major infrastructure project we anticipated reducing the HOH by 10% but when test results were received it had reduced the HOH by over 25% over control. Going by this reduction in HOH, it is reasonable to say it completely removed the incidence of HOH in these 1.2 meter thick slabs. It is a case-by-case situation as to whether you should decide to eliminate internal cooling manifolds.

Does CLEVA CRETE react differently when white cement and titanium dioxide rich material is utilised?

CLEVA CRETE works very well with it and we generally find an increased MPa when using white cement instead of the typical 13 to 17% increase. We have witnessed up to 25% increase in early strength in concrete where the cementitious material is white cement.

How does CLEVA CRETE work with colours? Can it assist with coloured panels which are typically drying out patchy?

It works extremely well with colours. Due to the dynamic active nature of creating C-S-H gel, on a nano sized level, it seems to cause all oxides to fully integrate in CCMC. The resultant colours gained are more true to character and are thus distributed evenly throughout the panel.

In most cases, unless batches are completely different, it creates a very even distribution of colours on high spec panels.

CLEVA CRETE – Partnering with you from the first pour to deliver superior waterproofing and durability within the concrete itself. Our innovative solutions save you time and reduce costs, ensuring sustainable project success.