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一、试验方法本试验试件尺寸为152×305毫米圆柱体,按ASTM C492-69或C684-74规定的试验方法进行养护。试模可采用重复使用的钢模、塑料模,也可用只用一次的薄金属板或塑料模。快速试验用钢模配有密封用的金属盖板。其他试模配有塑料盖子。快速试验用的圆柱体试件,成型以后立即放在35±3℃的水中。经23.5小时±30分钟养护后,从槽中取出并拆模。在24小时±15分钟内压试完毕。二、材料和试验拌制混凝土用的材料来自美国各地。Ⅰ类(普通)硅酸盐水泥取自18个产地;Ⅱ类(中热)硅酸盐水泥取自15个产地;火山灰和粉煤灰有5个产地。细骨料有天然砂和人工砂两种。粗骨料名义最大粒径
First, the test method The test specimen size is 152 × 305 mm cylinder, according to ASTM C492-69 or C684-74 specified test methods for curing. Trial molds can be reusable steel molds, plastic molds, or thin metal plates or plastic molds that are used only once. Rapid test steel molds are equipped with metal covers for sealing. Other test molds are equipped with plastic lids. The cylindrical specimens for rapid testing were immediately placed in 35±3°C water after molding. After 23.5 hours ± 30 minutes of curing, remove from the tank and remove the mold. The test was completed within 24 hours ± 15 minutes. Materials and Tests Materials used for mixing concrete are from various parts of the United States. Type I (ordinary) Portland cement was taken from 18 producing areas; Type II (medium heat) Portland cement was taken from 15 producing areas; volcanic ash and fly ash had 5 producing areas. Fine aggregates are natural sand and artificial sand. Coarse aggregate nominal maximum diameter