So what exactly is cement?

Lafarge Cement’s Bill Price goes back to basics

Many of us can remember when all cement in bags was ‘Ordinary’ Portland cement or ‘OPC’ – nice and simple. All cement was basically the same and you made your choice on the basis of price, availability and brand loyalty. Easy for the customer and easy for the merchant! But now, there seems to be a huge range of different cements all with a different code marked on the bag.

So, what exactly is a CEM II/A-LL or a CEM II/B-V* and how do they differ from the OPC of old?

As ever, the clue lies in the spread of European standardisation. At the turn of the millennium, a new Europe-wide standard was developed, bringing together a wide range of traditional common cements (CEMs) used throughout Europe into a single document

So, in the great scheme of things, OPC became CEM I and all other cements were given different ‘CEM’ numbers. The CEM II family of cements contain other materials in addition to Portland cement, but they meet the same standards and perform in a similar way. In most cases these additional materials react with the Portland cement (OPC) component to produce cementing compounds almost identical to those produced by simple OPC. Most cement producers will have plenty of information on their websites regarding the particular benefits of different CEM II cements.

So does any of this really matter for the builder’s merchant? The answer is yes – because with every change there is an opportunity…

The really big advantage is that the new CEM IIs are much more sustainable than the old OPC but still perform well. It takes less energy to produce them and considerably less CO2 is emitted during production.

Moreover, the additional constituents are often derived from the waste products of other industries, such as fly ash (the ‘V’ code) from power stations and fine limestone powder (the ‘L’ or ‘LL’ code), some of which would undoubtedly have ended up in landfill. In these days of increasing concern for the environment, selling CEM II cement is a positive statement about your own commitment to sustainability.

It is also a tick-box for those customers who are trying to minimise their own environmental footprint.

The amount of CEM II cement in the UK market is increasing year on year while CEM I (OPC) is becoming a rarity. So, whilst you will undoubtedly be selling a range of cements, you might also need to remind customers that not all the bags on display are still ‘OPC’ – and that choosing a more sustainable option is the best solution for everyone.

* CEM II/A-LL is a Portland-limestone cement with 6-20% limestone and CEM II/B-V is a Portland-fly ash cement with 21-35% fly ash

Bill Price is national commercial technical manager at Lafarge Cement UK. Keep up with him on Twitter @ConcreteDrBill