Promotion Mechanism Of Strength Development Of Electrothermal Curing Cement-based Materials

With the rapid development of construction industrialization,prefabricated buildings are also widely used in practical production.In order to improve the production efficiency of prefabricated buildings,the first task is to increase the demolding strength of prefabricated components.At present,several commonly used methods to promote the rapid development of concrete strength have certain limitations,so this study proposes a method to promote the speed of concrete strength development through electrothermal curing,which can improve the demolding strength of concrete,speed up mold turnover and improve production efficiency in a short time,which is of great significance for the development of prefabricated buildings.This paper focuses on the influence of several factors such as electrothermal curing parameters,curing process and material composition on the performance of electrothermal curing cement-based materials,including mechanical properties,carbonation resistance and microstructure.,and reveals the promotion mechanism of electrothermal curing on the strength development of cement-based materials,which provide a basis for the preparation and application of electrothermal curing concrete.The main work and research results of this institute are:(1)Influence of electrothermal curing on mechanical properties of mortar specimensBy changing the parameters of electrothermal curing,electrothermal curing process,water-cement ratio and the proportion of mineral admixture,the compressive strength of the electrothermal curing rubber specimen under different influencing factors was determined,and the influence of these factors on the mechanical properties of the electrothermal curing mortar specimens was analyzed.The results of the study indicate that electrothermal curing can effectively promote the development of the demoulding strength of the mortar specimens,and at appropriate electrothermal curing parameters(pre-curing time 4h,constant temperature time 8h,constant temperature 60 ° C)and curing process(pre-stage Covered with film + wet felt cloth for electrothermal curing,and standard curing after electrothermal curing is completed),it is not much different from the compressive strength of standard curing rubber specimens at various ages.The demoulding strength of the electrothermal curing rubber specimens increased greatly with the decrease of water-cement ratio,and the later strength growth increased with the increase of water-cement ratio.The addition of mineral admixture can improve the demoulding strength of the electrothermal curing motar specimen to a certain extent,and has a beneficial effect on the later strength.Among them,the suitable dosage of slag is 30%,and the suitable dosage of silica fume is 20%..(2)The influence of electrothermal curing on the carbonation resistance of mortar specimensBased on the influence of electrothermal curing on the mechanical properties of the mortar specimen in the previous section,the carbonization depth of the electrothermal curing mortar test piece under different influencing factors was measured by the accelerated carbonization test,and the influence of these factors on the carbonization resistance of the electrothermal curing motar specimens was analyzed.The results show that the carbonization depth of the electrothermal curing mortar specimens increases with the decrease of pre-curing time,increases with the increase of constant temperature time,and increases with the increase of constant temperature temperature.After the constant temperature time exceeds 8h and the constant temperature temperature is higher than 60 ° C,the carbonization depth of the electrothermal curing motar specimens increases significantly,and the anti-carbonization ability decreases significantly.Reasonable coverage method can be used to improve the carbonization resistance of the specimen to a certain extent during the electrothermal curing process.After the electrothermal curing,the carbonization resistance of the specimens with standard curing is better than the specimens cured in water,and the longer the water curing time,the worse the resistance to carbonization.For low-water-cement ratio(w/c?0.4)electrothermal curing mortar specimens,the carbonation depth of each age has not changed significantly,and the anti-carbonization ability is significantly higher than that of the same age high water-cement ratio(w/c = 0.5)mortar specimens.After adding slag,the carbonization depth of the electrothermal curing rubber specimen is slightly higher than that of the specimen without slag,and the overall gap is very small.The addition of silica fume greatly increased the carbonization depth of the electrothermal curing mortar specimens,and with the increase of the silica fume content,the increase was greater.(3)The influence of electrothermal curing on the microstructure of cement hydrationThe XRD test was used to analyze the phase composition of cement hydration products after electrothermal curing.The influence of electrothermal curing on the microscopic morphology of cement hydration products was analyzed by scanning electron microscope.At the same time,the influence of mineral admixture on the micro-morphology of the electrothermal curing mortar specimen was also analyzed.The research results show that,compared with standard curing,electric curing does not change the phase composition of cement hydration products.The samples after electrothermal curing have more hydration products,but the uniformity is lower than the standard curing samples,and the overall compactness is lower than the standard curing samples.The addition of mineral admixture can improve the compactness of the slurry to a certain extent.The paper has 33 pictures,27 tables and 81 references.