Different Maintenance Methods On The Performance Of Mixed Mortars

Over-exploitation of natural river sand has led to ecological damage and scarcity of river sand resources,and also made the shortage of fine aggregates in construction materials,mainly concrete,more and more prominent.Considering this status quo,the national policy calls for finding suitable substitutes,which has attracted extensive attention from many scholars.In this paper,based on the summary of previous results,we systematically study the mechanism sand and desalinated sea sand,and believe that the practice of mixing mechanism sand and desalinated sea sand has the possibility of replacing river sand as fine aggregate,and in further research,we find that when the mixing ratio is good,the mixed sand can combine the advantages of both,overcome the existing systemic problems,and increase the economic benefits of fine aggregate and relieve the environmental pressure while obtaining sand fine aggregate with excellent performance.After determining the material ratio and forming the specimens,the curing stage is the key to determine the quality of concrete specimens,which is time-consuming,labor-intensive,energy-consuming,difficult to adapt to complex working conditions,and does not meet the concept of green energy conservation and environmental protection.In this paper,four different curing methods will be used to cure the mortar prepared by mixed sand,and through performance tests and microscopic analysis,the effects of several curing on the performance of mixed sand mortar will be explored,and finally an optimal curing method will be sought to achieve green construction and energy saving and environmental protection from material to molding curing while obtaining a better curing effect.The main conclusions and contents are as follows:(1)In order to get the mixing ratio of mixed sand,the physical parameters of single sand type are systematically studied,and finally the mixing principle is proposed,and the parameters of mixed sand reach the optimum when the mixing ratio is 6:4 through the method of trial matching and testing.(2)Through experimental research and practice of internal maintenance material SAP(polymer resin)doping theory and doping method,the calculated standard dosing of SAP;reveal the influence of two doping methods of dry dosing and pre-absorption,and draw the action mechanism of the two doping methods.The test results show that the effect of SAP introduced by dry blending is better than that of pre-absorption under the same blending amount and similar water-cement ratio.(3)After determining the mixing ratio of mixed sand,the calculated optimal amount of SAP and the blending method,the standard blending amount is calculated according to SAP,and the blending gradient is set to study the effect of different amounts of SAP on the basic physical properties of mixed sand mortar,which shows that the basic physical properties are best when the blending amount is 1.5SAP.(4)In the test of the effect of maintenance methods on mechanical properties,the mechanical properties under four types of maintenance methods were studied in comparison,and the results showed that the best mechanical properties were achieved by using internal and external maintenance,and the 28 d compressive strength was higher than that of the standard maintenance group.(5)The test results show that the effect of internal maintenance on the frost resistance is similar to the effect of air-entraining agent,which can significantly improve the frost resistance.Meanwhile,the application of external maintenance can further reduce the loss of strength after freeze-thaw cycles and make up for the shortcomings of internal maintenance.In the refinement study of internal and external maintenance,the best maintenance method is to use 1.5SAP dose for internal maintenance and apply external maintenance at the same time.