钙硅比对生物质灰渣加气混凝土性能的影响

Influence of Calcium-Silicon Ratio on Performance of Biomass Ash Aerated Concrete

生物质灰渣含有较高的SiO_2和CaO,与水泥、石灰等按一定的比例混掺,制备生物质灰渣加气混凝土砌块。实验通过改变生物质灰渣、粉煤灰和石灰的相对含量,调节加气混凝土砌块的钙硅比,并研究了钙硅比对其水化产物、机械力学性能和微观结构的影响。结果显示,随着钙硅比的增大,生物质灰渣加气混凝土砌块的干密度逐渐增大,钙硅比为0.86时,强度达到峰值,其抗压强度和抗折强度分别为2.5 MPa和1.8 MPa,且托勃莫来石的生成量也达到最大。干燥收缩图也表明钙硅比为0.86时,生物质灰渣加气混凝土砌块的体积性能最好,其最大干燥收缩率为0.44 mm/m,优于国家标准(0.5 mm/m)。水化产物电镜图谱表明随着钙硅比的增加,生物质灰渣加气混凝土砌块的水化产物形貌由针棒状结构转变为片状结构。

Biomass ash contains high Si02 and CaO.It is mixed with cement,lime and so on according to a certain proportion to prepare biomass ash aerated concrete blocks.Calcium-silicon ratio of aerated concrete was adjusted to research its influence on hydration products,mechanical properties and microstructure by changing the relative content of biomass ash,fly ash and lime.Results show that with increase of calcium-silicon ratio,dry density of biomass ash aerated concrete blocks gradually increase.When the calcium-silicon ratio is 0.86,the intensity reached its peak,its compressive strength and flexural strength is 2.5 MPa and 1.8 MPa,respectively.And the production of tobermorite is also the largest.Dry shrinkage figure also shows that biomass ash aerated concrete blocks have excellent volume performance when the calcium-silicon ratio is 0.86,and its maximum dry shrinkage is 0.44 mm/m,better than national standard(0.5 mm/m).Electron microscopy map of hydration products shows that with increase of calcium-silicon ratio,hydration products morphology of biomass ash aerated concrete blocks transformed from elongated needle-like structure to lamellar structure.