(一)日本高强混凝土发展概况1940年,日本采用高压脱水法,减少混凝土的水灰比,从而制得了抗压强度达800～1000公斤/厘米~3以上的高强混凝土。由于高强混凝土允许应力大,耐冲击性能良好,近几年来,在制桩行业中,得到了广泛应用。使用高强混凝土制作基础桩,不仅其混凝土的抗渗性、耐久性、耐 (1) Development of high-strength concrete in Japan In 1940, Japan adopted a high-pressure dehydration method to reduce the water-cement ratio of concrete, thereby producing a high-strength concrete with a compressive strength of 800 to 1,000 kg/cm 3 or more. Because high-strength concrete allows high stress and good impact resistance, it has been widely used in the pile-making industry in recent years. Using high-strength concrete to make foundation piles not only impermeability, durability, and durability of concrete