Effect Of Concrete Components On The Shrinkage And Cracking-resistant Of Concrete

Shrinkage deformation properties of concrete have been one of the hot anddifficult problems in the concrete research. Shrinkage cracking of concrete hasbecome a common phenomenon in modern concrete sector, and has seriously affectedthe normal use and service life of the building structure. A wide range use and deepresearch of the chemical admixtures and mineral admixture can meet the social needsof sustainable development. But the use of chemical and mineral asmixture has takena challenge to the traditional test methods and theoretical system. There are manyproblems in the traditional test method of shrinkage, quantitative analysis ofsuppression and cracking, cracking risk assessment method. These problems haveseriously restricted the research progress of concrete shrinkage and cracking, and alsolimited the broader application of the chemical and mineral admixture in projects.This paper studied the influence of different water-reducing agent on dryingshrinkage and shrinkage cracking of concrete under different W/C, and the influenceof mineral admixtures on concrete autogenous shrinkage, drying shrinkage andcracking performance was the research focus too. In this study, using different testmethods to study concrete shrinkage and cracking property, and using the ternarycementitious system to design and analysis experiments, and combined the theoreticalresearch and engineering.Volume change method and contact-free shrinkage test method are used to studythe influence of the different mineral admixtures and water-reducing agent on theconcrete shrinkage performance. Polycarboxylate water-reducing agent can greatlyreduce the drying shrinkage of concrete. The incorporation of fly ash significantlyinhibit the drying shrinkage of concrete and early autogenous shrinkage of mortar, andmore fly ash, the the shrinkage decreases is greater. The slag with Blaine finess of446m2/kg replace cement, the drying shrinkage of concrete significantly increased, andthe greater content the more effect (the content less than50%). But the same slagcement replacement will reduce the early autogenous shrinkage of mortar in concrete.Using the ternary cementitious design and analysis methods to determine fly ash andslag optimum dosage in good property of concrete shrinkage.Ring test method was used to study the impact of different mineral admixturesand water-reducing agent to the property of cracking resistance. And use the ring test method to quantitatively analyz the property of cracking resistance. Polycarboxy latewater-reducing agent can significantly improve the property of cracking resistance.Fly ash could significantly inhibit concrete cracking, and can greatly reduce theinternal stress of the concrete. Incorporation of slag will increase the risk of conc retecracking and can increase the internal stress of the concrete. Using the ternarycementitious design and analysis methods to determine fly ash and slag optimumdosage in good property of cracking resistance.In this paper advanced test methods in shrinkage and cracking of concrete areused. Thia methods were used to study the impact of variety of factors in shrinkagecracking of concrete. These factors include mineral admixtures (fly ash and slag),water-reducing agent type, concrete strength etc. This paper presents a controlconcrete shrinkage cracking method of using mineral admixtures and water-reducingagent.