为了给工程安全使用提供借鉴，采用浸泡腐蚀法研究钢筋HRB400在3.5%NaCl溶液中裸露和镶入混凝土2种环境下腐蚀行为及腐蚀后的力学性能，对于钢筋HRB400镶入混凝土这种环境，采用制作钢筋混凝土及模拟混凝土孔隙液2种方法，首先将裸露和镶入混凝土2种情况下的钢筋HRB400浸泡在3.5%（质量分数）NaCl溶液中，并将钢筋HRB400浸泡在饱和氢氧化钙溶液中[加入3.5%（质量分数）NaCl溶液]，然后分别计算不同腐蚀时间下各钢筋HRB400相应的失重率、腐蚀率，最后采用MTS试验机测试钢筋HRB400腐蚀后的力学性能。结果显示：随着浸泡腐蚀时间延长，3种环境下的钢筋HRB400平均腐蚀速率逐渐降低，失重率增加，屈服强度、抗拉强度均下降，钢筋HBR400在3.5%NaCl溶液中裸露或镶入混凝土时伸长率随浸泡时间延长而降低，在饱和氢氧化钙（加入3.5%NaCl）中则呈现有升有降趋势。

In order to provide references for the safe use in engineering applications, the corrosion behavior and post-corrosion mechanical properties of HRB400 reinforcement steel, exposed to a 3.5% NaCl solution in two distinct environments-bare and embedded in concrete were investigated through immersion corrosion test. For HRB400 reinforcement steel embedded in concrete, two approaches were employed: the fabrication of reinforced concrete and the simulation of concrete pore fluid. Initially, HRB400 reinforcement steel, both in bare form and embedded in concrete, was immersed in a 3.5% (mass fraction, the same below) NaCl solution. And soaking the HRB400 reinforcement steel in a saturated calcium hydroxide solution (with addition of 3.5% NaCl solution). The weight loss rate and corrosion rate of the HRB400 reinforcement steel under different corrosion times were calculated separately. Subsequently, the mechanical properties of the corroded HRB400 reinforcement steel were assessed using MTS testing machine. Results showed that as the immersion corrosion time prolonged, the average corrosion rate of HRB400 reinforcement steel across the three environments gradually decreased, while the rate of weight loss increased. Additionally, there was a decline in yield strength, tensile strength, and elongation rate. In the 3.5%NaCl solution, the elongation of HBR400 reinforcement steel in bare form and embedded in concrete decreased with the extension of soak time. However, in the saturated calcium hydroxide solutionl (with addition of 3.5%NaCl solution), the elongation showed a trend of mcreasing and decreasing.