碱激发矿渣/粉煤灰净浆/砂浆力学性能研究

Mechanical Properties of Alkali-Activated Slag/Fly Ash Paste/Mortar

开展碱激发材料力学性能的研究有利于促进其在实际工程中的应用。本文研究了矿渣掺量及细骨料掺量对碱激发净浆/砂浆抗压强度、弹性模量及应力-应变曲线的影响。结果表明:矿渣的掺入能够显著提高碱激发净浆/砂浆的抗压强度和弹性模量;细骨料掺量增多会降低抗压强度,但会提高弹性模量。净浆28 d弹性模量在12.83~19.53 GPa,砂浆28 d弹性模量在18.72~23.10 GPa。细骨料掺量为40%(质量分数)时,砂浆峰值应力和峰值应变出现明显下降,弹性模量变大。采用分段式方程对碱激发矿渣/粉煤灰净浆/砂浆的应力-应变曲线进行拟合,拟合曲线与实测曲线吻合良好。拟合结果表明碱激发净浆/砂浆应力-应变下降段曲线随矿渣掺量与龄期增加而变陡,反映材料脆性增强,与上升段曲线规律一致。

Study on the mechanical properties of alkali-activated materials is able to promote its practical application in engineering. In this paper, the effects of slag content and fine aggregate content on the compressive strength, elastic modulus and stress-strain curves of alkali-activated paste/mortar were investigated. The results show that the addition of slag significantly improves the compressive strength and elastic modulus of alkali-activated paste/mortar. The addition of fine aggregate reduces the compressive strength while improves the elastic modulus. The elastic modulus of alkali-activated slag/fly ash paste ranges from 12.83 GPa to 19.53 GPa at 28 d. The elastic modulus of alkali-activated slag/fly ash mortar ranges from 18.72 GPa to 23.10 GPa at 28 d. When the amount of fine aggregate is 40%(mass fraction), the peak stress and peak strain decrease obviously while elastic modulus increases. The piecewise equation is used to fit the stress-strain curves of alkali-activated slag/fly ash paste/mortar. The fitting curves are in good agreement with the measured curves. The fitting results indicate that the stress-strain curves of alkali-activated slag/fly ash paste/mortar become steeper with the increase of slag content and the curing age, reflecting the brittleness of materials, which is consistent with the rising curves.