Mechanical properties of microbially modified recycled aggregate concrete and establishment of a constitutive model
By substituting recycled aggregates(RA)for natural aggregates(NA),it is possible to reuse leftover concrete,consume less energy,and advance the sustainable development of building materials.In order to improve the defects of recycled aggregate and improve the performance of recycled concrete,the mineralization and deposition characteristics of basophilic aerobic Bacillus Coriolis were used to strengthen and modify recycled aggregate,and the influence of the concentration of bacterial solution on the basic mechanical properties of recycled aggregate was investigated.Modeling the uniaxial compression configuration of modified recycled aggregate concrete(RAC)and examine the mechanical characteristics of modified RAC under various replacement rates.The test results demonstrate the effectiveness of microbial mineralization deposition technology in enhancing the apparent density of RA,decreasing water absorption,and lowering the crushing index.The optimal bacterial liquid concentration for the modification effect is 1.265 × 108 cells/mL;At this concentration,the crushing index may be decreased from 13.0%to 10.8%and the water absorption of RA can be decreased from 4%to 2.4%before modification;When the substitution rate of RA obtained by less than 40%,the compressive strength of recycled concrete does not vary significantly;The compressive strength of normal aggregate concrete(NAC)crease of 7.73%when the substitution rate was 100%.The split tensile strength of RAC with 100%RC substitution rate is lower than that of NAC,and the split tensile strength of RAC with 40%RC substitution rate is 15%greater than that of NAC.This is in addition to the RA replacement rate of 100%;except when the replacement ratio of RA is 40%,RAC has a lower flexural strength than NAC.Considering the mechanical properties and economic applicability of RAC,this paper takes the RA substitution rate of 40%as the best aggregate replacement rate.The research results can provide reference for the application of RAC in practical engineering.
mineralized sedimentationrecycled aggregatesreplacement raterecycled concretemechanical characteristicsconstitutive model