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Putting cement under the microscope to help improve its performance

By understanding and changing how crystals form in cement, scientists are finding ways to reduce the impact of concrete on the environment.

SDG Case study G9.4 Cement Robinson

8 October 2020

Cement forms the basis of concrete–the single most widely used material in the world.

“Manufacture of cementworldwide accounts forapproximatelyeightper centofallhuman-producedcarbon dioxide,” explains Professor Ian Robinson(鶹ýƵվ Centre for Nanotechnology).

Professor Robinson’sresearchaimstoadjust thecompositionofcement so it can act as a carbon sink andoffsetsome of thecarbon dioxideproduced during its manufacture.

However,the complexity ofcement manufacture andthewaycritical components of cement reactwith each other, affect how the concrete performs.Ifchemical reactions within the cement aresuboptimal,theconcreteweakens, which can end indisaster.For example,adulterated cementcontributed tothewidespreadcollapse ofbuildingsduringanearthquake in Izmit, Turkey,in 1999,whichkilled17,000 people.

This wouldpartially replace cement clinker– an important component of cement manufacture produced athigh temperature in a kiln –savingenergy and reducingCO2emissions

Professor Robinson’s team is using X-ray imaging methods, developed using the UK’s Synchrotron, to understand the performance of cement and concrete materials, working in collaboration with theSchool of Materials Science and Engineering,Tongji University, Shanghai.

“Oneof our goals is to make smallchangesincement’scomposition, without spoilingitsperformance,” he explains. “For example,byaddingappropriateamounts ofindustry by-products such asfly ashand granulated blast furnace slag.

This wouldpartially replace cement clinker– an important component of cement manufacture produced athigh temperature in a kiln –savingenergy and reducingCO2 emissions during cement production, as well asreducingtheimpact on theenvironment for the life of the cement.

“We arelookingatcalcite–a compound thatformsduringcementhydration andcan actas a carbon sink,”Professor Robinson explains.

UsingX-ray imaging,the team isclosely examiningcalcite nanocrystalgrowthinhigh and lowCO2conditionstocheck for irregularities and defects in the crystal structure that could affectthe concrete’sperformance.