摘要
膨胀混凝土通过结晶性钙矾石或氧化镁的生成实现硬化后期的膨胀性能。化学外加剂通过如缓凝剂或高效减水剂的掺加往往改变结晶型膨胀组分的形成速率进而影响膨胀混凝土的后期膨胀性能。通过研究对比萘磺酸盐甲醛缩合物(FDN)与接枝共聚羧酸类超塑化剂(PCA)以及四种缓凝剂对钙矾石类与氧化镁类膨胀混凝土变形性能的影响。研究发现,与高效减水剂相比,缓凝剂对两类膨胀混凝土的膨胀性能影响较大,其中糖类以及有机磷类缓凝剂较为适合钙矾石类膨胀混凝土在饱水养护下的膨胀性能发展,而有机磷类缓凝剂更加适合氧化镁类膨胀混凝土饱水养护下膨胀性能发展。对于两种膨胀混凝土而言,饱水养护才能保证混凝土的后期持续膨胀。
The expansion of expansive concrete are due to the crystallization of magnesium oxide or ettringite formation during the continuous hydration process after its setting.Chemical additives, such as retarders or superplasticizers,affect the deformation of expansive concrete by alterlating the crystalline formation rate of the expansvie crystalline components.The expansion deformation properties of ettringite type and category of magnesium expansive concrete were comparing studied by adding admixutes of naphthalene sulfonate formaldehyde condensation（FDN） and graft poly-carboxylate based superplasticizer（PCA） and four retarders.It is found that retarders had marked effect on the deformation properties of the two types of expansive concrete than the two superplasticizers.Retarders based on sugars and organic phosphorus were more appropriate for the expansive development of entrigate type expansive concrete cured in wate,while organic phosphonic category retarder was more appropriate for that of the magnesium type expansive concrete cured in water.The two expansion concrete only cured in water showed a sustanined expansive characteristic.
出处
《混凝土》
CAS
CSCD
北大核心
2008年第11期50-52,共3页
Concrete
基金
2007年江苏省自然科学基金(BK2007722)
关键词
缓凝剂
高效减水剂
膨胀混凝土
收缩
膨胀
retarder
superplasticizer
expansive concrete
shrinkage
expansion
