Tag Archives: Construction material

What can you do using cement? Funny stuff made of cement

It is well known that cement is the most used construction material in the world. In the mind of most of people, cement is a kind of grey powder and only used as construction material, to build gardens, bridges, road etc. However, we can do more with cement, here are nice pictures showing some stuff made of cement. Creactive!

Even as a guy like me who deals with cement everyday, I really think these items are pretty funny. What do you think you can do using cement? make the most of your imagination, dare to think.

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The Importance of Cement and its Future

Concrete is the most used material in the world because of its cheap price and large quantity. It is needless to say concrete is made of cement. However, cement is also a criticized material by the public, for its intensive CO2 emission from production process. The production of cement accounts for about 5-8% of the non-natural CO2 worldwide.

Importance of Cement

Importance of Cement

Importance of Cement

People may ask, can we find an alternative construction material instead of cement? such as wood, steel. The annual usage of wood is much above the replanting level, and it is not possible to get wood in some places such as Africa and China. As for steel, it is costly and again the production of steel also gives CO2 emission. Furthermore, the production of cement is not that energy intensive compared with other materials.

Importance of Cement

Actually, it is not possible to find an alternative construction material. 98% of the earth’s crust is made of eight elements: O, Si, Al, Fe, Ca, Na, K, Mg, which are the main elements of cement as well. From the long term run, the world will still need a large amount of cement. The demand of cement mainly comes from developing countries, such as India and China because of the urbanization and its population growth.

Importance of Cement

Importance of Cement

Importance of Cement

Since we have to use cement in the future, how can we do to reduce the CO2 emission and what is the future of cement? Efforts have been doing ever since decades ago in the cement industry and research community.

On the one hand, cement plants nowadays burn (hazardous) waste, say, car tyres, as fuel to make cement. The wood floating on the water of Three Gorges Dam is even collected to make fuel for cement plants. On the other hand, the production process of cement has always been optimizing. Some cement plants can even reach 80% efficiency, which is a great achievement even from a theoretical standpoint.

Importance of Cement

Importance of Cement

Researchers of cement try to use less cement clinkers. One viable method is Supplementary Cementitious Materials (SCMs). SCMs are commonly industry by-products or raw materials, such as Slag, limestone, Fly ash, silica fume, natural pozzolan. Whether binary blended or even ternary blended, SCMs can replace part of cement without sacrificing equivalent engineering properties.

Importance of Cement

Considering the limited quantity and access of SCMs, SCMs are not a permanent sustainable way from a long term run. Some researchers are trying to utilize the unlimited amount of calcined clay, for the kaolinite content of clay has similar cementitious property. Work done replacing 30% of cement by calcined clay in Cuba shows the potential future of clay if well used.

Importance of Cement

Generally speaking, cement is a significantly important construction material, and it is not necessary to worry that much as for the CO2 emission in the future.

What is cement and its history?

Cement, the gray and fine powder, is the most used construction material on the world. However, how many people do they know what cement is? the answer for this question from Wikipedia is as follows,

In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word “cement” traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder.

The reason why cement can sets and hardens independently is its hydraulic property. When cement is mixed with water, the chemical reaction occurs and produces hydration products, such as C-S-H gel, calcium hydroxide, ettringite and monosulfoaluminate. The C-S-H gel is the main material to bind different particles and resulting in the engineering strength which is needed as a construction material.Since the set and hardening process of cement is chemical reaction, so we can get cement set under water.

What is cement?

Cement (Source: Wikipedia)

As for the chemical composition of cement, there are four essential elements in cement, which are Calcium, Silicon, Aluminum and Iron. The four elements form four clinkers, namely,

  • Tricalcium silicate (3CaO.SiO2), (50-70%)
  • Dicalcium silicate (2CaO.SiO2), (15-30%)
  • Tricalcium aluminate (3CaO.Al2O3), (5-10%)
  • Tetracalcium aluminoferrite (4CaO.Al2O3.Fe2O3), (5-15%)

If you would like to know the production process how cement is made, refer to this web page or the video below.

It is common to see another name of cement that is Portland cement, because concrete made with cement resembled natural stone from the Isle of Portland. It worthy to note that first cement is produced by early Greeks and Romans from volcanic ash mixed with slaked lime. Unfortunately, this art was lost during the Middle Ages. The modern cement, Portland cement, is developed in England by bricklayer Joseph Aspdin in early 1800’s.