关键词: 风积沙混凝土, 相对动弹性模量, 风积沙掺量, 硫酸镁浓度, 孔隙率, 钙矾石

Abstract: Taking aeolian sand concrete as research object, the micro-pore structure, micro-morphology and product characteristics of concrete under different aeolian sand content and different concentration of sulfate erosion were observed by nuclear magnetic resonance, field emission scanning electron microscope and energy spectrometer. The results show that with the increase of aeolian sand content, the compressive strength of aeolian sand concrete increases first and then decreases, and the porosity decreases first and then increases. When the content of aeolian sand is 40% (mass fraction), the mechanical properties are the best. With the increase of magnesium sulfate concentration and the extension of erosion period, the relative dynamic elastic modulus of aeolian sand concrete increases first and then decreases. When the concentration of magnesium sulfate is 3.5% and the content of aeolian sand is 40%, the aeolian sand concrete still meets the standard requirements after soaking for 360 d. At this time, the porosity of aeolian sand concrete is 2.553%, of which the proportion of less harmful and harmful pores reaches 63.8%, and more needle-like ettringite is produced. When the concentration of magnesium sulfate is 5.0% (mass fraction), the porosity increases to 2.879%, the proportion of less harmful and harmful pores decreases to 57.3%, and the enrichment degree of ettringite further increases.

Key words: aeolian sand concrete, relative dynamic elastic modulus, aeolian sand content, magnesium sulfate concentration, porosity, ettringite