Study On The Performances Of Concrete Utilizing Waste Foamed Basalt As Recycled Aggregates

With the acceleration of the urbanization process,construction waste is increasing,the problems of energy shortage and environmental pollution have become increasingly prominent.Energy conservation has become an important guarantee for sustainable development.It is an effective way to solve waste foamed basalt as the recycled lightweight aggregates,which replace the traditional aggregates as part or all of the aggregates of concrete.In order to provide technical support for promoting the application of foamed basalt recycled aggregate in concrete and provide theoretical support for the development and application of energy-saving wall,this paper will focus on the waste foamed basalt.Foamed basalt aggregate will be evaluated and be used in lightweight aggregate concrete and normal concrete,and various performances of the concrete will be studied.Specific studies are as follows:(1)The quality evaluation of foamed basalt aggregates were developed,and the basic properties of foamed basalt lightweight aggregate were obtained by comparing the apparent density,water absorption,water content and cylinder strength between the foamed basalt aggregate and shale ceramsite.(2)With different replacement rates of foamed basalt aggregate,The mechanical properties,shrinkage properties,frost resistance and thermal performance of 390 specimens of lightweight aggregate concrete were developed.The cube compressive strength,splitting tensile strength,flexural strength were measured.The damage morphology of the specimen was observed,and the optimum dosage range of the foamed basalt aggregate was obtained.The factors influencing the strength of the concrete were analyzed.The shrinkage rate was t ested with time.The factors influencing the shrinkage were analyzed.The frost resistance of lightweight aggregate concrete was studied by using air entraining agent and Wrapping treatment.The methods of improving frost resistance of lightweight aggregate concrete were proposed.The thermal conductivity of concrete slabs was tested.The relationship between the thermal conductivity and the content of foamed basalt aggregate was analyzed.The best foamed basalt aggregate replacement rate value was obtained.The internal morphology of lightweight aggregate and the interface structure of coarse aggregate – cement stone were obtained by scanning electron microscopy(SEM).(3)With different replacement rates of foamed basalt fine aggregate,the mechanical properties of 75 specimens of normal concrete were studied and the best foamed basalt aggregate replacement rate value was obtained.The stress-strain curve of the specimens was analyzed,and the variation of elastic modulus,peak stress,peak strain and ultimate strain were discussed.The change law of the parameters of the rising and falling segments of the stress-strain curve was given by the method of polynomial fitting,and uniaxial compression constitutive model was established.The application of concrete with foamed basalt aggregate in practical engineering was discussed.