Comprehensive Estimation of Expansive Energy Produced by Expansive Admixture and Static Expansive Demolition Agent

当膨胀剂的单位掺量超过60 kg/m~3时，单轴约束膨胀混凝土的抗压强度和杨氏模量开始因过度膨胀而降低。在膨胀混凝土中掺入钢纤维可以有效地缓解膨胀混凝土的性能劣化，当外置钢管对膨胀混凝土进行径向约束时，即使在膨胀剂的单位掺量为90 kg/m3时，膨胀混凝土的抗压强度和杨氏模量也保持与普通混凝土相同。即使提供钢管来抑制径向膨胀，化学压力对膨胀混凝土力学性能的影响也是难以预料的。只有在三轴约束的情况下，才能清楚地观察到化学加压的效果。通过对两根不同直径、不同厚度的钢管进行同心排列，观察到三年龄前的化学挤压效应。膨胀混凝土被放置在内外管道之间。在这些管子的约束下测量了膨胀应变。无论钢管的布置和数量如何，膨胀混凝土在钢管上所做的径向功都可以假定为恒定的。由于钢管与膨胀混凝土之间的粘结对膨胀能的限制较小，纵向功小于径向功。静态膨胀破碎剂灌浆的膨胀能测量困难，因为浆液中温度上升很快。

Compressive strength and Young's modulus of uniaxially restrained expansive concrete began to decrease due to an excessive expansion when an unit content of expansive admixture was over 60kg/m^3. A phenomenon of anisotropic behaviors of mechanical properties in expansive concrete was observed. Addition of steel fibers in expansive concrete was effective to alleviate deterioration of the properties.When the expansive concrete was restrained radially by an outside placed steel pipe, the compressive strength and Young's modulus was respectively retained the same as one of ordinary concrete even when the unit content of expansive admixture was 90kg/m^3.The effect of chemical press on the mechanical properties of expansive concrete was scarcely anticipated even if the steel pipe was provided to restrain a radial expansion. Only in the case of triaxial restraint, the effect of chemical press was clearly observed. The chemical press effect was also observed up to the age of three years.Two steel pipes with different diameter and thickness were arranged concentrically. The expansive concrete was placed between the outside and inside pipes. Expansive strains were measured under the restraint of these pipes. The radial work done by expansive concrete on steel pipes can be assumed to be constant regardless of an arrangement and an amount of steel pipes. The longitudinal work was smaller than the radial one due to a less restraint of expansive energy by a bond between steel pipe and expansive concrete.Measurements of expansive energy of a grout with static expansive demolition agent were found difficult due to a rapid rise of temperature in the grout.