粉煤灰中铵含量对水泥胶砂性能影响及限值研究

Effect of ammonium content on cement mortar and its limitation in fly ash

研究了粉煤灰中铵含量对粉煤灰性能、水泥净浆和水泥胶砂性能的影响。结果表明:随着粉煤灰中铵含量的增大,粉煤灰的需水量比逐渐增大、活性指数逐渐降低,水泥净浆标准稠度用水量逐渐增大、净浆凝结时间逐渐延长,水泥砂浆含气量逐渐升高、胶砂流动度和抗压强度逐渐降低。一般工程情况下用于水泥及胶砂中粉煤灰铵含量的限值为200 ppm。

The effects of ammonium content in fly ash on properties of fly ash,cement paste and cement mortar were studied.The results show that with the increase of ammonium content in fly ash,the water demand ratio of fly ash increases,the strength activity index decreases,the water requirement of normal consistency increases,the setting time lengthens,the heat of hydration of cement decreases,the air content of cement mortar increases,and the fluidity and strength of cement mortar decreases.The limitation of ammonium content is 200 ppm in fly ash used in cement and mortar.