The Effect of Na-K Activator and Curing Mode on Fly Ash-based Geopolymers
This paper reports the results of the study of the influences of concentration and modulus of sodium potassium silicate solution (Na-K activator) and curing mode on the phase composition,microstructure and strength development in the geopolymers prepared using Class F fly ash.X-ray diffraction (XRD),Fourier transform infrared spectroscopy (FTIR) and MAS NMR are utilized in this study.It shows that the compressive strength increases while sodium potassium silicate solution modulus increases,but when modulus exceeds 1.7,the compressive strength decreases,and it decreases markedly while modulus is greater than 2.0.The compressive strength improves with increase of sodium potassium silicate solution concentration.When the concentration is 36%,the compressive strength reaches the maximum.Elevated temperature can increase the strength of samples synthesized using sodium potassium silicate solution with 32% concentration and modulus 1.2.Compared to the strength of the sample cured at 50℃,the strength of the samples cured at 65℃ and 80℃ are higher at 1 day and 3 days,but when cured at 80℃,strength is smaller than that cured at 50℃ for 7 days.When temperature is too high,too long curing time will decrease the strength.Long precuring at room temperature before application of heat is beneficial for strength development,and there is about 10%～50% increase in strength of the samples cured at 1 day recuring and 2 days elevated temperature as compared to the strengths of the samples cured for 3 days at elevated temperature or cured for 28 days at room temperature.The main product of reaction in the geopolymeric material is amorphous alkali aluminosilicate gel.
Geopolymers Fly ahs Activator Curing mode
Y.F.Hou D.M.Wang Q.Li
Beijing Institute of Civil Engineering and Architecture,Beijing,China.
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
3780-3785
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）