高掺量粉煤灰泡沫混凝土干缩和耐久性研究

Study on Drying Shrinkage and Durability of High Content Fly Ash Foam Concrete

为进一步提高泡沫混凝土的干缩、耐久及力学性能,文中在泡沫混凝土中掺入不同量的粉煤灰,分析粗粉煤灰对泡沫混凝土的力学性能、收缩性能和耐久性的影响。试验结果表明,细骨料/FAc和FAc的56 d强度分别是细骨料混凝土强度值的2.6倍和2.0倍;混凝土仅掺入细骨料时,最大强度为11 MPa,50%细骨料/50%FAc的最大强度为19 MPa,混凝土全部掺入粗粉煤灰时,最大强度仅为17 MPa。同时,掺细骨料泡沫混凝土的干燥收缩率随密度的增加而减小,掺粗粉煤灰泡沫混凝土的干缩率则完全呈增大趋势。泡沫混凝土的密度越高,混凝土中加入的细骨料和水就越多。

In order to further improve the drying shrinkage and durability of foam concrete,improve the mechanical properties of foam concrete,and improve the potential of foam concrete as a lightweight filling material for subgrade.In this paper,different amounts of fly ash are added into foam concrete,and the influence of coarse fly ash on the mechanical properties,shrinkage properties and durability of foam concrete is further analyzed.The experimental results show that the 56 day strength of fine aggregate/FAc and FAc is 2.6 times and 2.0 times the strength value of fine aggregate concrete,respectively.When only fine aggregate is added to the concrete,the maximum strength is 11 MPa,while the maximum strength of 50% fine aggregate/50% FAc is 19 MPa.When all coarse fly ash is added to the concrete,the maximum strength is only 17 MPa.And the dry shrinkage of foam concrete with fine aggregate only decreases with the increase of density,while the dry shrinkage of foam concrete with coarse fly ash completely increases.The higher the density of foam concrete,the more fine aggregate and water will be added to the concrete.