CEMEX Extra is manufactured by burning a precisely specified mixture of raw materials containing lime, silica, alumina and small quantities of other materials to form a clinker. The clinker, a selected fly ash and calcium sulfate, (to control setting), are inter-ground to produce a very consistent cement with improved characteristics. CEMEX Extra is suitable for use as an alternative to Sulfateresisting Portland cement in most aggressive ground conditions.
CEMEX is committed to continuous improvement in environmental and sustainability performance, particularly through utilising recycled content, minimising landfill waste and improving our energy efficiency.
CEM II cements are factory produced Portland composite cements. CEM II cements from CEMEX are of the Portland-fly ash type. This product contains a minimum of 25% fly ash which is a by-product of Coal Fired Power Stations, making not only a more sustainable cement but also enhancing it's performance characteristics.
To produce a durable concrete using CEMEX Extra, the cement content of the mix must be maintained at an acceptable level. BS8500-2; Concrete, (Complementary British Standard to BS EN 206-1), gives guidance for using a CEM II/B-V cement in concrete, under various exposure conditions.
Once in place, concrete requires moisture to develop its full strength and premature drying out must be avoided. In normal conditions and at temperatures in excess of 10ºC, concrete should be cured under damp conditions for 1 to 3 days, (cover with curing membrane, plastic sheeting or wet hessian); at temperatures below 10ºC, this curing time should be doubled. Curing is particularly important with CEM II cements as early strengths may be slightly lower than for CEM I products. Protection against freezing is required until the concrete reaches a compressive strength of 5 MPa
All normal concrete admixtures (e.g. plasticisers, air-entrainers, retarders) may be used with CEMEX Extra. Trials should, however, be carried out to establish required dosage rates and air-entrainers should be suitable for use with fly ash.
A range of admixtures complying with BS EN 934 are also available from CEMEX.
Mixes to resist chemical attack
Please refer to the latest version of the Building Research Establishment (BRE) Special Digest 1.
The applicable SD1 notation for CEMEX Extra is CEM II/B-V + SR which should be used to obtain recommended minimum cement contents and maximum water:cement ratios required for classes of aggressive ground conditions.
CEMEX cements conforming to the harmonised European standard, BS EN 197-1, are subject to rigorous third party certification procedures by an EU Notified Body, in accordance with assessment and verification of constancy of performance (AVCP) system 1+.
Declarations of Performance in respect of essential characteristics, are available from our UK website (www.cemex.co.uk/cemarks).
The CE marking is affixed to packaging and/or despatch documents as required by the Construction Products Regulation.
Certification scheme features
- Independent confirmation that products comply fully with technical specification.
- Independent audit testing of products by UKAS accredited laboratories.
- Independent evaluation of test data and appraisal of factory production control.
- Traceability of cement deliveries to the manufacturing works.
- Most rigorous AVCP system (1+) specified in the Construction Products Regulation
Routine test data including fineness, setting time, soundness, alkali and chloride levels and BS EN 196-1 mortar prism strengths are available in the form of weekly Cement Test Reports. Other test data including chemical analyses are also available on request.
Data on principal products are also available electronically. Contact using the contact form or on 0800 353 433 for further details and registration.
Delivered in pressurised bulk powder tankers by road, the standard load size is 28 - 30 tonnes. Silo identity disks can be provided for individual products by calling Customer Services on 0800 353433.
Make sure you’re ready to receive and store your bulk material by viewing the checklist
All CEMEX drivers are fully trained and experienced in the discharging of our vehicles, please do all you can to ensure your site is accessible with no obstructions. If you are in any doubt, we can send an engineer to advise you - just ask.
To avoid premature deterioration of the reducing agent incorporated in the cement for control of soluble chromium (VI), storage should be in accordance with our recommendations given on despatch documents.