粗集料筛分试验

粗集料筛分试验（T0302—2000）Coarse aggregate screening test (T0302 - 2000)一，目的与适用范围\Purposes and applicable ranges测定粗集料（碎石，砾石，矿渣等）的颗粒级配。

Determine the grain composition of coarse aggregate (macadam, gravel and slag, etc) 二，仪具与材料Instruments and materials试验筛：根据需要选用规定的标准筛。

天平：感量不大于试样质量的0.1%。

浅盘，小铲，毛刷。

烘箱：能控制105±5℃。

Test sieve: select the specified standard sieve according to the requirementsScale: the sensitivity is not greater than 0.1% of the sample massStray, small shove, hair brush, oven: can be controlled at 105±5℃三，试验准备Preparations将试样用四分法筛分至如表要求的试样所需量，每种试样准备两份，分别供水洗法和干筛法筛分使用。

Divide the sample with quartering method to the required amount as the following chart. Prepare two servings of each sample, which is used respectively for water-washing method and dry-sieving method.筛分用的试样质量（kg）the mass of sample which is used for sieving对水泥混凝土集料，如果没有要求，也可不进行水洗只进行干筛筛分。

将试样放入105±5℃烘箱中，烘干至恒重。

烘干至恒重后取出，在室温下冷却。

The concrete cement aggregate, if not required, only needs dry sieving without water washing.Put the samples into the oven with 105±5℃, Keep drying the aggregates till they have a constant weight. Then take the samples out and cool at room temperature.四，实验步骤Test procedures用水洗法测定集料中小于0.075mm的细粉部分质量，取试样一份，称取干燥集料试样m，准确至0.1%。

将试样置于一洁净容器中，加入足够数量的洁净水，将集料全的总质量1部盖没。

用搅棒充分搅拌集料，使集料表面洗涤干净，使细粉悬浮于水中，但不得破碎集料或集料从水中溅出。

仔细将水盆中混有细粉的悬浮液倒入套筛中，尽量不把粗集料倒出损坏标准筛筛面。

再次加水于水盆中，重复上述步骤，直至倒出的水洁净为止。

将水盆中的试样全部倒入浅盘中，水盆上不能有粘附的集料颗粒，将透筛的每一个筛子上的试样用少量水洗入浅盘中。

将浅盘连同集料一同放入105±5℃的烘箱中烘干。

烘干至恒重后取出冷却，在m。

准确至0.1%。

室温下冷却，待冷却至室温后称干燥集料试样的总质量2Determine the mass of aggregates which are smaller than 0.075mm with water-washing method,m, be accurate to 0.1%. select one sample and weigh the total mass of dried aggregate samples1Place a specimen in a clean container and add clean water in sufficient quantities till the aggregates are all covered by water. Wash and clean the aggregates surfaces by mixing the aggregates with stirring rod so that the powder could be suspended in the water. But pay attention not to crush the aggregates or make the aggregates splash from the water. Pour the suspension mixed with powder carefully from the basin into the sieve seat. Try not to pour out the coarse aggregates which might cause damages to the standard sieve. Then add water again in the basin and repeat the above-mentioned steps till the water poured out is clean. Pour all samples from the basin to the stray; there should not be aggregate particles adhesion on the basin. Wash the sample residues attached on the platter with a small amount of water into the stray. Dry the stray with aggregates in the oven at a temperature of 105±5℃. Keep drying the aggregates till they have a constant weight. Then take the stray out and cool it at the room temperature. Cool and Wait till itm, be accurate to 0.1% is at room temperature, weigh the total mass of dried aggregate samples2用干筛法测定粗集料各个粒级质量百分率m，准确至0.1%。

用搪瓷盆做筛分容器，称取另一份烘干至恒重的干燥集料试样总质量按筛孔大小排列顺序逐个将集料过筛，当筛余颗粒的粒径大于20毫米时，筛分过程中允许用手指亲亲拨动颗粒，但不得逐个塞过筛孔，如果某个筛上的集料过多，影响筛分作业时可以分两次筛分，人工筛分时需使集料在筛面上同时有水平方向及上下方向不停顿的运动，使小于筛孔的集料通过筛孔直至一分钟内通过筛孔的质量小于筛上残余量的1%为止。

将筛出的颗粒并入下一号筛，和下一号筛中的试样一起过筛，顺序进行，直至各号筛全部筛完为止。

以确认一分钟内通过筛孔的质量确实小于筛上残余量的1%。

采用摇筛机筛分后应该逐个由人工补筛，称取每个筛上的筛余量准确至总质量的0.1%。

m相比。

其相差不得超过0.5%。

各筛分计筛余量及筛底存量的总和与筛分前的总质量Determine the mass percentage of various aggregate grades with dry-sieving methodWeigh the total mass of another sample which is dried to a constant weight, be accurate to 0.1%. Take the enamel basin as screening container; sieve each grade of aggregates one by one according to the order of screen hole size. When the diameter of particle residues is greater than 20mm, you are allowed to touch gently with fingers, but not allowed to push the aggregates thorough the screen individually. If there are too many aggregate residues to influence the sieving work, you can divide the work in two parts and sieve. When do artificial screening, you should keep the aggregates moving along the horizontal and vertical direction on the screen, which in order to make the aggregates whose sizes are smaller than the hole size pass through the screen until the mass of the aggregates which pass through the screen within 1min is less than 1% of the mass of residues left on the screen. Put and sieve the pass-through aggregates together with the next type of screen. Sieve in order until all types of sieves are finished. Make sure the mass of the aggregates which pass through the screen within 1min is less than 1% of the mass of residues left on the screen. After being sieved by the screen shaker, additional manual screening work should be done as well. Weigh the mass of residues on each sieve; be accurate to 0.1% of the total mass. Compare to the total mass of unscreened aggregates 0m , the difference of the summation of each screening residues and sieve stocks and the total mass of unscreened aggregates 0m should not be greater than 0.5%.五，计算1， 集料中通过0.075mm 的含量按下式计算，准确至0.1%。