The Study Of Partial Performance Of Concrete Prepared With Cement Containing Different Clinker Mineral Content

The call of “time is money, efficiency is life” in the construction industry makesthe development of cement and concrete along early strength and high strengthdirection. This unscientific orientation leads to excessive pursuit of high content ofhigh strength, early strength mineral such as C₃S, C₃Aand bigger specific surface areain the production process of cement industry. It not only makes more energyconsumption in the clinker production, higher demand of limestone resources, moreemissions of environmentally unfriendly gas such as CO₂, NO_x, also leads to seriousconcrete structures cracking, the degradation of some performance affecting to thedurable service life of the project, especially in highway project and prestressed pipeindustry, which have a large consumption of cement. For example, poor fatigueresistance and wear resistance has become one of the important reasons for thedamage of concrete road; pile breaking rate rises because of bad impact resistance ofconcrete. The resources, energy waste have already been very outstanding. So, it issignificant for the development of cement and concrete industry, to study therelationship between the mineral content of clinker and the fatigue resistance, impactresistance, wear resistance of concrete, to evaluate the reasonable mineral content ofclinker from the social view of energy saving and emission reduction.In this article, four kinds of industrial clinker were selected containing differentmineral content produced by the5000t/d precalcining kiln. They were grinded to350m²/kg PI cement in the laboratory mill, in order to prepare the same strength gradeof concrete in the same proportion. The effects of different mineral content on thestrength, fatigue resistance, impact resistance, wear resistance of concrete werestudied. The mechanism was analyzed through TG-DSC, EDS, SEM.The results were obtained as follows. When the content of silicate mineral C₃S,C₂S in clinker was similar, with the increment of Fe₂O₃in the cement, the content ofC₄AF would increase, and the content of C₃A would reduce. The fatigue resistance,impact resistance, wear resistance of prepared concrete also increased at28and90 days. If the content of C₃S was enough to meet the strength requirement of cementand the content of solvent mineral C₃A, C₄AF was similar, the fatigue resistance,impact resistance, wear resistance of concrete prepared with low C₃S high C₂S cementwere better than the concrete prepared with high C₃S low C₂S cement. There werelower ratio of crystal gel in the hydration products of C₂S, which had more C-S-H geland lower CH content. The later hydration of C₄AF consumed partial CH, reduced theCH enrichment and the crack birthplace in concrete interface, and then optimized theinterface structure between the coarse aggregate and mortar. So the concrete preparedwith cement containing more C₂S and C₄AF had higher toughness, higher fractureenergy, slower sub-critical crack propagation rate, and thus fatigue resistance, impactresistance, wear resistance were better.