Comparision of Maintenance Methods for Fly Ash/gypsum/calces Brickwork

Three maintenance methods,including natural maintenance,wet maintenance,and steamy maintenance,are comparatively investigated in this study by emphasizing their effects on the intensity and chemical components of fly ash-gypsum-calces brickwork.Experimental results show that the intensities for samples prepared under steamy maintenance are more twice than those prepared under natural maintenance and wet maintenance.XRD results revealed that cacoclasite(2CaO·Al₂O₃·SiO₂) is the main hydrated phase for samples prepared under natural maintenance,anorthite(CaO·Al₂O₃·2SiO₂) for ones prepared under wet maintenance and ettringite(3CaO·Al₂O₃·3CaSO₄·32H₂O) for ones prepared under steamy maintenance.SEM observations indicate that the pozzolanic reaction incompletely proceedes in the samples prepared under natural maintenance and wet maintenance,with a number of floating beads present in the hydrated phase.Whereas,for the samples prepared under steamy maintenance,the pozzolanic reaction completely proceed,and floating beads thoroughly disappear in the hydrated phase.Mechanism analysis suggests that the joint contribution of chemical stimulation and thermal stimulation is responsible for much higher intensity of samples prepared under steamy maintenance.