煅烧煤矸石混凝土徐变性能正交试验研究

为研究不同煅烧温度、煤矸石质量取代、粉煤灰质量取代、水灰比的混凝土抗徐变性能,开展了4因素3水平的正交试验,对不同条件的混凝土试件开展为期120 d的干缩和徐变研究。结果表明:基础养护28 d抗压强度受水灰比和煤矸石质量取代影响较大;干缩变形从基础养护28 d后算起第70 d为分界线,分为快速干缩和稳定干缩两阶段,受煅烧温度和水灰比影响较大;适当的粉煤灰质量取代和煅烧温度可抑制干缩;持荷120 d,徐变变形整体增大,大致可分为快速、慢速、平缓3个阶段,受煤矸石质量取代和煅烧温度影响较大,徐变变形和时间有较高的相关性;适当的粉煤灰质量取代和煅烧温度可致密空隙,降低水化热反应,抑制干缩变形和徐变变形。

Orthogonal Test Study on Creep Performance of Calcination Coal Gangue Concrete

In order to study the creep resistance of concrete with different calcination temperatures, coal gangue mass substitution, fly ash mass substitution and water-cement ratio,four factors and three levels of orthogonal experiments were carried out. The concrete specimens under different conditions were subjected to a 120 d study of dry shrinkage and creep. The result shows that:the compressive strength is greatly affected by water- cement ratio and gangue quality substitution when the foundation curing is 28 d. Dry shrinkage deformation is the dividing line at 70 d after 28 d of foundation maintenance , which divided into two stages, rapid dry shrinkage and stable dry shrinkage, and there is greatly affected by calcination temperature and water-cement ratio. Proper fly ash mass substitution and calcination temperature can restrain dry shrinkage. With load holding for 120d, as a whole ,creep deformation increases, which can be roughly divided into three stages: fast, slow and gentle. It is greatly affected by the replacement of gangue quality and calcination temperature, and there is a high correlation between creep deformation and time. Proper fly ash mass substitution and calcination temperature can compact the void, reduce hydration heat reaction and restrain dry shrinkage deformation or creep deformation.