A geologist friend of mine recently told me his favourite joke: “Two planets meet out there in space. Says the first: “You know, I am not feeling well lately – I discovered I have got homo sapiens!” Answers the second: “Don’t worry – that will fade out by itself very soon!”
Don’t worry: I am not going to talk about climate change again (really?), but what is so striking about this joke, is the obvious difference in timeframes for planets and mankind. And don’t we know this perceived asynchronicity in many occasions of our everyday life ourselves? Our industries – building materials, cement – is commonly perceived as an extremely conservative community where 10 or 20 years mean no big time range. Compared to fashion or consumer goods we are seen to be turning into dinosaurs even before we have run half way through our projects. However, when it comes to making sure, that the 20 year old building still remains safe and the 30 year old tunnel through the alps still does not collapse, our dear friends from the fashion industry are happy that we tend to think in decades and centuries rather than months and years…
We are actually living in interesting times (as a Chinese curse goes). We are witnessing as mankind changes to the recipe of man’s most fabricated product after only 2000 years! Ever since its first use, cement has been manufactured predominantly from limestone. Only recently – and that not only according to geological terms – man has begun to switch that to a radically higher portion of clay. Numerous proposals to reduce the portion of limestone-based Portland clinker in cement or cementitious products have come up during the last decades and this substitution forms one of the most potential pathways towards the required CO2-emission reduction of the industry.
For sure, it will still be a long way to go until we will have arrived at a low carbon cement world, but we will get there. We will get there because there is no real alternative to cement as the main building material for mankind on earth. Even though alternative materials will have their share, the sheer magnitude of the required volumes prohibits the use of wood or other biogenic material to fill the gap. Other anorganic material is not available in the sufficient amount, so we are definitely going to use cement in the future as well. But what it takes is to accommodate new recipes and production methods for that cement and concrete. And with all necessary scrutiny to be applied (think of the buildings and tunnels), this may require to shift timeframing from “good-old days” to “urgent”!