Study On Self-repairing Reinforcement Materials For Rammed Earth Wall Of Earth Building

Fujian Tulou is located in the southeast coastal area of China.It often suffers from severe weather such as rainstorms and typhoons.Many Tulou buildings have a history of hundreds of years.Although they have not collapsed after hundreds of years of severe storms and rainstorms,the accumulated wind and rain erosion over the years has caused considerable damage to the rammed earth walls of Tulou buildings.In the long run,it will gradually engulf the rammed earth walls of Tulou buildings,causing huge losses to these buildings.The protection of flowers is very important.Based on the theory of microbial-induced mineralization,this paper uses microbial technology to achieve self-repair of cracks in rammed earth wall of earth building,mixing microorganisms with other reagents to form self-repair agent dissolved in mud;when cracks occur,microorganisms fill cracks with Ca²⁺induced mineralization products in cracks,so as to achieve the purpose of self-repair of rammed earth wall of earth building,and provide one for repair and protection of earth building.Define the practical reference significance.Through the study of microbial growth characteristics and enzymatic activities in the external environment,the results show that microorganisms are not conducive to the survival of microorganisms in high alkali environment and do not have good enzymatic activity under the condition of pH value about 10.Therefore,gypsum is used as the carrier of microorganisms to provide a viable environment for microorganisms;the addition of remediation agent will affect the performance of mud materials.It causes the decrease of fluidity,the delay of setting time and the loss of strength,but it will not affect the performance of mud material obviously in the suitable range of dosage.In the aspect of crack prefabrication,in order to make the specimen to be repaired which meets the test requirements,the"embedded method"is used to make cracks,which is similar to the real cracks formed in natural environment.Then,when evaluating the self-repairing effect of cracks,the area repairing rate,i.e.image method,is adopted,because it is simpler and more applicable than other methods such as seepage method and deposition depth method.Further study on the effect of crack repair under different factors shows that the effect of crack repair does not increase infinitely with the increase of the amount of repair agent,and good repair effect can be achieved when the amount of self-repair agent is6%.In the aspect of crack,the repair effect decreases with the increase of crack width,and for the crack whose width is less than 0.5mm,the effect can be improved.For cracks larger than 0.9mm,it is impossible to achieve a higher level of repair;for temperature,when it is higher or lower,it is not conducive to crack repair,and the best repair effect can be obtained at about 30?.For its maintenance,the use of geotextile covering with sprinkler water and wet maintenance can not achieve crack repair,but the test proves that dry-wet cycle or immersion maintenance can be achieved.Good repair effect.