Research On Weathering Reinforcement And Salt Damage Control Of Outdoor Masonry Cultural Relics

As an important physical witness of the development of human society,the relics’ the extermal environment,the material composition,structure and performance of cultural have changed over time,causing cultural themselves to suffer from dif-ferent degrees of damage.Take the brick and stone relics as an example,they are preserved mostly in the natural environment in a large number,distributed widely and suffered from physical and chemieal weathering for a long time.Therefore,it is a task with great social demand to study the reinforcement materials and maintenance methods of brick and stone relics with excellent performance.Traditional inorganic reinforcement material compatibility is good but in desalting,reinforcement performance and other aspects can not reach the great effect.The organic reinforcement materials’ weatherability are poor,in addition to the high price,not only lacking the function of desalting,but having the strict requirements of soluble salt content.Therefore,it has become an innovative idea to study reinforcement materials with desalination function,and the research of reinforcement materials and process technology are the key and difficult point.This paper will conduct research from the following six aspects:1.Familiar with the research background and formulating research ideas.Before carrying out the system experiment,first of all,a large number of literatures should be consulted to understand the application situation and evaluation principle of protection materials.The commonly used reinforcement materials are classified and their advantages and disadvantages are analyzed.Then the performance index and the theory mechanism of the reinforcement material need to be evaluated are defined,so as to design the research idea.2.The basic performance study of two-component reinforcement materials.According to the requirements of the reinforcement materials evaluation,this part of work focuses on the permeability of reinforcement materials,tests samples’ color difference,gas permeability,storage of salt,salt permeability,and detects samples’mechanical parameters of damping drill strength,unconfined compressive strength,shear strength and nonmetal ultrasonic mechanical indicators after the accelerated aging experiments.The results show that the two-component reinforcement materials have good applicability and weather resistance.3.Mechanism of salt damage control of two-component reinforcement materials.The research with a view to the failure mechanism of soluble salt,under the environment of simulating distribution of soluble salt(NaCl,KCl and Na2SO4),operating steps contain reinforcement and desalination.By means of XRD,XRF,SEM-Mapping and damping anti-drillers such modem scientific instruments,research has tracks the flow and conversion process of salt.The final results show that this inorganic reinforcement materials can not only reinforce samples,but has the ability to turn the most destructive salt Na2SO4 into the main component BaSO4 of barite irreversibly,and the above two steps can finish at the same time.4.The mechanism of action of each component in two-component reinforcement materials.This study takes remoulded soil sample of fine uniformity and excellent repeatability as the research object,splitting the two component reinforcement materials and designing single component and combination reinforcement with the adjustments of combination,concentration and times.The author linearly calculate the regression equation of samples1 Maximum pressure resistance,systematically summarize the reinforcement rules of each component and explain the possible reasons of reinforcement rule combining with the results of color difference and sEM-EDAX.It turned out that Ba(OH)2 and H3po4-Ba(OH)2 group are prominent in evaluation of mechanical effect.The above is of certain reference value for the selection of reinforcement materials for soil sites.5.The study on the salting-out inhibition of Na2B8O13·4H2O.This part work puts Na2B8O13·4H2O as salting-out inhibitor.Macroscopically,it has significant inhibitory effect on the common soluble salts Na2SO4 and NaCl and will not affect the original water imbibition.After accelerated aging,samples protected by inhibitors have excellent performance on unconfined compressive strength and nonmetal ultrasonic mechanical indicators.The inhibitors have played an important role in protecting cultural relics intensity.Then,by the characterization methods of XRD、IR、TG、SEM-EDS and SEM-Mapping,the mechanism of inhibition is researched.It turned out that the characteristic peak-OH(3460 cm-1)increasing significantly and the characteristic peak Na-O(810 cm-1)appearing makes Na2B8O13·4H2O envelop Na2SO4 with the existence of gel state on the micro level.6.The application of cultural relics protection engineering.Two-component reinforcement materials and inhibitors-Na2B8O13·4H2O were used in four cultural relic units-guangyuan qianfo cliff,yungang grottoes,Shimao ruins,and Chairman MAO statue of shanxi university.From the current tracking results,the suitability and weatherability of the two-component reinforcement materials can withstand the test of the natural environment,and inhibitors also showed excellent protection performance.