The Research On Cement Super Gelatinization Theory And Technology

On the basis of general ordinary Portland cement, the online design theory andtechnology system with low energy consumption in cement super-gel was established,so as to satisfy the demand of modern concrete for low water/cement ratio and highflow regime. It aims to solve major problems existied in the requirements of modernconcrete and its general technology. The concrete with20%~40%energy-intensivecement is unable to fully hydrate and its gel efficiency is low. When the water/cementratio is below0.437, the cement clinker, and act as aggregate filling, which is unableto completely hydrated, therefore causing huge waste. The anhydrate cement mayproduce calcium hydroxide concentration in the interface of transition zone inconcrete, therefore leading to durability deterioration of concrete, etc.Based on the above problems, this paper puts forward a new kind of cementonline processing theory and technology with regard to concrete application. It’srelying on some projects, such as the973national key basic research developmentplans, the national natural science foundation of China (51178363). Technologiessuch as particle shaping and truing, gradation controlling and optimizing, surfacemodification and charge balance technology are used. We conduct systematicresearch focused on low carbon preparation, surface modification and improvementof gel efficiency. The leverage cement online processing technology was used toincrease gel efficiency of cement, reducing the dosage of cement clinker with highresource or energy consumption and carbon emission, and improving interfacialtransition zone of concrete to improve the durability of concrete.The main achievements and innovations of the articles listed as follows:1. To overcome the low grinding efficiency and high energy consumption thecement online processing and preparation technology was established, based ondistribution function and granularity fractal dimension theory.The breakthrough was made in the traditional grinding method featuring lowefficiency and high heat loss converted from energy consumption, originally proposethe online processing technology on ordinary Portland cement (C) by usingmicro-grinding medium (M). The systematic theory and key technology was established with low energy consumption in super-gel regarding concrete application.Based on normal, lognormal, Gaudin-Schumann and Rosin-Rrammler distributionfunction and granularity fractal dimension theory, the systematically the particle size(frequency distribution and cumulative distribution), the characteristic parameters(D50, D10, D25, D75and D90) and the granularity fractal dimension D of three kindsof material system (C, M, and CM) by using two kinds of grinding method werestudied. Then, the theoretical foundation was established with high grindingefficiency and low energy consumption of super-gel. Under the experimentalconditions, compared with the ordinary cement using traditional grinding technology,when particle size D50is8um, processing for10minutes after adding5%M andprocessing for5minutes after adding20%M, energy consumption per unit mass ofthe processing technology reduce29.83%and58.33%, respectively. When particlesize D50is7um, processing for10minutes after adding20%M and processing for5minutes after adding30%M, energy consumption per unit mass was reduced37.50%and64.29%, respectively.2. To meet low water/cement ratio, high fluidy of concrete, and to solve thereunion of the cement caused by the reduing of cement particle size problem, thesurface modification and control technology of super-gel of cement wasestablished, using IPP image technique, fractal prinpcle and electronic shelltheory.The surface modification agents by different types and dosages was used tocontrol fractal dimension of flocculated structure, particle surface potential and yieldstress of cement paste. Under the experimental conditions, the fractal dimension ofsuper-gel paste is1.2~1.4. The zeta potential of hydration is-60mW~-30mW. At60min, when the shear rate is100r/s-1, the shear stress is320pa~500pa, theviscosity is4.00pa·s~5.00pa·s. While the ordinary cement fractal dimension is1.4632, the shear rate is100r/s-1,60min hydration of zeta potential is0.89mW. At60min, when the shear rate is100r/s-1, the shear stress is579.27pa, the viscosity is9.45pa·s. Based on lowering fractal dimension of super-gel paste, which is increasingelectrone gativity of ζ potential, reducing shear stress and viscosity lay theoreticalfoundation for its application in the low water/cement ratio, high flow, high strengthand high durability of modern concrete. The leverage surface modification and design of super-gel paste to establish the model of cement particle fractal dimension-zetapotential-rheological properties, form cement dispersing technology and theoreticalfoundation, propose quick evaluation and analysis of the degree of particle dispersion.3. Based on hydration products, hydration degree and interfacial transitionzone of super-gel cement, the super-gel cement theory and model was established,to lay theoretical foundation for super-gel cement using in high strength anddurability modern concrete.Many methods were adopt such as XRD, SEM and DTA-TG to analyze thedegree and features of hydration of super-gel cement at different ages and underdifferent water/cement ratio, to establish hydration theory and model of cement.Compared with the ordinary cement, under the same condition, the hydration degreeof super-gel cement obviously improved22.04%after hydrating for1d,10%for3d,and20%for180d. The structure of super-gel cement’s hydration products is morecompact than that of potland cement. Where the peak strength of characteristicdiffraction maximum of Ca(OH)2in hydration products was increased. The weightloss of the hydration products increased, ether. Compared with ordinary cement,under the experimental conditions, the hardness of super-gel cement in interfacetransition zone increased20.95%, the size decreased24.14%, and the hardness of theslurry increased14.29%. The increasing compact of the structure of hydrationproduct, declining concentration of Ca(OH)2lay theoretical foundation for itsapplication in improvement of strength and durability of concrete.4. The application effect of super-gel cement was studied in concrete ofdifferent systems. The system and key technology of concrete and theoreticalfoundationforthe application and popularization of super-gel cement wasestablished.The application effect of super-gel cement in concrete of different systems wasstudy and the system and key technology of concrete was established. Undercomparative mechanical property, super-gel cement and ash are untilized to replacePortland cement in unit volume of concrete with8.33%super-gel cement and30.00%cement is reduced of gel material cost. Or we adopt super-gel cement and fly ash toreplace Portland cement with super-gel cement, when the dosage is16.67%,25.00%cement is reduced. Or we adopt super-gel cement, fly ash and mineral powder to replace Portland cement with8.33%super-gel cement,30.00%cement is reduced.The material flow balance of industrial application of super-gel cement was studyiedand analyzed, and industrial application flow chart was draw, therefore layingtheoretical foundation and key technology for application and popularization ofsuper-gel cement.