基于温度-应力试验的掺膨胀剂混凝土抗裂性能研究

通过温度-应力试验研究了钙质和镁质膨胀剂(Type-CaO, Type-MgO)对混凝土早期抗开裂性能的影响。结果表明,掺10%Type-MgO和Type-CaO膨胀剂混凝土的绝热温升较基准混凝土分别提高了3.6%和14.0%,断裂温度相对基准混凝土分别降低了9.7℃和1.7℃;约束条件下,掺10%Type-MgO膨胀剂混凝土的极限拉伸值和断裂应力相对基准混凝土均提高约27%,而掺10%Type-CaO膨胀剂混凝土的极限拉伸值和断裂应力与基准混凝土无明显区别;数据表明,镁质膨胀剂相比钙质膨胀剂可以明显提高混凝土的早期抗开裂性能,钙质膨胀剂不宜用于大体积混凝土的裂缝控制。

Study on the Early-age Cracking Resistance of Concrete with Expansive Agent Using Temperature-stress Testing Machine

The early-age cracking resistance of concrete with CaO and MgO expansive agent were investigated based on the temperature-stress testing. The results show that compared with reference concrete, the adiabatic temperature rise of concrete with 10% MgO and CaO expansive agent tested in adiabatic model increases by 3.6% and 14.0%, and the cracking temperature decreases by 9.7 ℃ and 1.7 ℃. In restrained condition, the ultimate extension value and cracking stress of concrete with 10% MgO expansive agent increase by 27%, while concrete with 10% CaO expansive agent has no significant difference with reference concrete. MgO expansive agent could evidently improve the early-age Cracking resistance of concrete, and CaO expansive agent can not be applied to crack control of mass concrete.