刨花高温处理对水泥刨花板水化热和弯曲性能影响的研究

水泥刨花板性能优良、耐水防火,植物原料刨花对水泥的固化具有一定的阻凝作用。采用高温干燥技术,探讨了刨花不同的高温处理条件(处理温度:130、170、210℃,处理时间:0.5、1.5、2.5h)对刨花和水泥混合物水化热以及水泥刨花板力学性能的影响。结果表明:1)刨花高温处理对刨花与水泥相容性的改变有明显的作用。刨花处理条件为210℃、2.5h时,水化温度上升最高,达到35.0℃比未处理刨花升高7.4℃,但是达到最高温的时间为1320min,并不是最短。刨花处理条件为170℃、2.5h时,相容性系数CT和CA分别为25.6%和104.0%,是所有处理条件中最好的。2)刨花高温处理对水泥刨花板所有龄期(分别养护7、14d和28d)的静曲强度总体呈现增强的趋势。在刨花处理条件为170℃、2.5h时,水泥刨花板28d的静曲强度(终强度)最大达到8.2MPa,比刨花未处理时增加了4.7MPa,提升了134%。

Effects of High Temperature Treatment of Wood Chips on the Hydration Heat and Modulus of Rupture of Cement Particleboard

Cement particleboard is a kind of building material with excellent performance such as water and fire resistance,which will have broad aspects in application.In the production of cement particleboard,the wood material will negatively affect the hardening of the cement.In order to solve this problem,this paper discussed the effects of the different high temperature treatments (temperature:130,170,and 210℃,time:0.5,1.5 h,and 2.5 h) of wood material on the properties of cement particleboard.The results showed that 1) the high temperature treatment of wood chips had obvious effects on the compatibility between wood and cement.The effect the treatment varied according to different evaluation methods.When the processing conditions were 210℃ and 2.5 h,the highest hydration temperature rose to 35.3℃,3.4℃ higher than untreated wood chips.But the time to achieve the maximum hydration temperature prolonged to 1 320 min.When the conditions were 170℃ and 2.5 h,the compatibility coefficient CT and CA were 25.6% and 104.0%,respectively,which were the best among all treatment conditions.2) The high temperature treatment of wood chips showed an increasing tendency to the static bending intensity of cement particleboard at all curing ages (7,14,and 28 days respectively).After 28 days of maintenance,cement particleboard was usually considered to reach the ultimate strength. The maximum modulus of rupture of cement particleboard reached 8.2 MPa and increased by 134%,when the processing condition of wood chips was 170℃ and 2.5 h.