Dioxide Cured Concrete Research

CO₂ concrete curing technology,integrating the global subject on CO₂ reclamation,utilization and fixation into concrete material science, has great significance in terms of concrete industry sustainable development and greenhouse gas emission reduction.Based on process parameter index of this technology and basic principles of curing process, this paper systematically studied problems of CO₂ curing process approach,mechanical properties of specimen after curing,effects of reaction kinetic parameters and micro mechanism change before and after curing process.Major work and conclusions in this paper are as follows:1.Proposes the approach of increasing CO₂ curing degree by appropriate pre-conditioning measures,and formed CO₂ curing process under comparatively low air pressure and high water cement ratio.The study shows that appropriate humidity of concrete itself is the most important factor to ensure smooth curing process.2.Fully studies intensity of CO₂ curing concrete.The study shows that specimen's CO₂ curing degree and intensity after curing are of logarithmic function relationship.By comparing the three curing systems of CO₂ curing,steam curing and standard curing,it shows that the early stage intensity with CO₂ curing is obviously superior to that with standard curing;and the later stage intensity with CO₂ curing is obviously superior to that with steam curing while the former is much the same as that in standard curing.3.Deduces and proves by experimental data the dynamic relation in CO₂ curing process,on the basis of Youngdle equation of solid state reaction.The temperature changes in CO₂ curing process is monitored with temperature measuring devices,and the changes conform well to dynamic experimental data.4.Analyzes the effects on reaction speed by four parameters including forming pressure,CO₂ pressure,vacuum degree and CO₂ concentration from dynamics perspective.The study finds out that the changes of these parameters have greater effects on early stage reaction, while the influence is little along with the ongoing of reaction process. 5.Studies main products and micro mechanism of specimen before and after CO₂ curing process with advanced testing measures like XRD, SEM and EDXA.The experiment results shows that during the CO₂ concrete curing process,main substances reacting with CO₂ are cement clinker particle,ettringite and Calcium Hydroxide;while cement clinker particle plays a major role in the whole curing process,and the reaction products after curing are calcium carbonate and silica gel.