随着“十四五”规划逐渐实施，基建规模日益扩大，建筑用砂资源紧缺，探究建筑用砂新来源成为工程界日益关注的问题。我国沙漠丰富，风积砂资源广泛，利用风积砂制备混凝土可有效缓解建筑用砂供需矛盾，又可降低建设成本。本文以陕北地区风积砂为原材料制备混凝土，开展力学特性试验、冻融循环试验，结合核磁共振技术，从宏细观角度研究不同因素对风积砂混凝土冻融劣化程度及力学特性的影响规律，建立冻融损伤模型与服役寿命预测模型，为风积砂混凝土在寒区工程实践中应用提供理论基础。主要研究内容及结论如下：

（1）基于坍落度试验及力学特性试验，研究了水胶比（0.42、0.45、0.48）、砂率（30%、32%、35%）、风积砂替代率（0%、20%、40%、60%、80%、100%）等因素对拌合物工作性能及混凝土力学特性的影响规律。结果表明：随水胶比的增大，混凝土坍落度逐渐增大，抗压强度逐渐减小；随砂率或风积砂替代率的增加，混凝土坍落度与抗压强度均呈现出先增大后减小的趋势。

（2）通过核磁共振技术分析了不同配比风积砂混凝土的孔隙结构特征，确立了强度与孔隙率之间的关系。结果表明：风积砂混凝土强度随总孔隙率增加呈线性减小，随着有害孔隙率增加非线性减小。基于有害孔隙率和总孔隙率双因素指标建立的孔结构-强度关系表达式与试验结果一致性较好。

（3）开展冻融循环及力学特性试验，并结合核磁共振技术，从宏细观角度研究了不同因素对风积砂混凝土抗冻性能的影响规律。结果表明：混凝土抗冻性与水胶比负相关，与砂率及风积砂替代率正相关，混凝土中小孔隙占比增多能够起到一定抵抗冻融破坏的作用，可改善抗冻性能。

（4）通过灰色关联度分析了各类孔径孔隙与冻融损伤的相关性，确立了无害孔隙率与混凝土质量损失率和动弹性模量损失率之间的关系；以无害孔隙率为指标定义了风积砂混凝土孔隙结构损伤，并基于此确立了风积砂混凝土服役寿命预测模型。

With the gradual implementation of the 14th Five-Year Plan, the scale of infrastructure is expanding, construction sand resources are in short supply. Exploring new sources of construction sand has became an increasingly concerned issue in the engineering community. China is rich in desert and eolian sand resources are extensive. Using eolian sand to prepare concrete can effectively alleviate the contradiction between supply and demand of construction sand and reduce the construction cost. In this paper, the aeolian sand in northern Shaanxi is used as raw material to prepare concrete. The mechanical properties test, freeze-thaw cycle test and nuclear magnetic resonance technology are carried out to study the influence of different factors on the freeze-thaw degradation degree and mechanical properties of aeolian sand concrete from the macro and micro perspective. The freeze-thaw damage model and service life prediction model are established, which provided a theoretical basis for the construction and application of aeolian sand concrete in cold regions. The main research contents and conclusions are as follows :

（1）Based on the slump test and mechanical properties test, the influences of water glue ratio (0.42, 0.45, 0.48), sand ratio (30 %, 32 %, 35 %), aeolian sand replacement ratio (0 %, 20 %, 40 %, 60 %, 80 %, 100 %) and other factors on the working performance of the mixture and the mechanical properties of concrete were studied. The results show that with the increase of water glue ratio, the slump of concrete increases and the compressive strength decreases. With the increase of sand ratio or aeolian sand replacement rate, the slump and compressive strength of concrete increase first and then decrease.

（2）The pore structure characteristics of different proportions of aeolian sand concrete were analyzed by NMR technology, and the relationship between strength and porosity was established. The results show that the strength of aeolian sand concrete decreases linearly with the increase of total porosity, and decreases nonlinearly with the increase of harmful porosity. The expression of pore structure-strength relationship based on the two-factor index of harmful porosity and total porosity is in good agreement with the test results.

（3）The influence of different factors on the frost resistance of aeolian sand concrete was studied from the macro and micro perspectives by conducting freeze-thaw cycles and mechanical properties tests, combined with nuclear magnetic resonance technology. The results show that the frost resistance of concrete is negatively correlated with the water glue ratio, and positively correlated with the sand rate and aeolian sand replacement rate. The increase in the proportion of small and medium pores in concrete can play a role in resisting freeze-thaw damage and improve the frost resistance.

（4）The correlation between various pore sizes and freeze-thaw damage was analyzed by grey correlation degree, and the relationship between harmless porosity and mass loss rate and dynamic elastic modulus loss rate of concrete was established. The damage of pore structure of aeolian sand concrete is defined with harmless porosity as the index, and the service life prediction model of aeolian sand concrete is established based on this.