混凝土坍落度试验

Knowing the quality of the concrete being used in construction is a requirement at building sites worldwide. 混凝土 slump testing is a quick 和 easy procedure that can be performed in real-time 和 on-site that is used to determine the workability as well as the consistency of fresh concrete. 混凝土 with slump values that are too low or too high can be identified 和 corrected prior to use.

混凝土坍落度试验设备

一些专业, 但相对便宜, testing equipment is required prior to perform the slump test. It is important that the equipment being used complies with international st和ards such as:

• ASTM C143, ASTM C11611, ASTM C192 和 ASTM C1712 as set by the American Society for Testing 和 Materials;
• AASHTO T119 和 AASHTO BS1881 as set by the American Association of State Highway 和 运输ation Officials;
• BS EN 12350-2 as set by the British & 欧洲标准
• 印度标准IS 1199-1959

It is important to obtain the following 项目 to perform the slump test:

• 坍落度筒: Cone shaped mold that can be made of 钢 or 塑料 和 should measure 8" (203mm) dia. 在基地，4“(102毫米)直径. 在顶部和12“(305毫米)高.
• 基板: The slump cone will sit on the base during the test 和 it should include bolt-on clamps to hold the cone steady during testing. A base plate with a h和le will make it easier to remove 和 can also be used as a guide to measure the slump.
• 捣固杆: A 钢 rod used during testing 和 should measure .625“(16mm)直径. X 24“(610毫米)长.
• 卷尺:用来衡量经济衰退.

The following 项目 are not required to perform the test itself, but will make the testing easier 和 can increase efficiency:

• 独家新闻: A round nose scoop with bowl dimensions 8.25“(210毫米)长度x 5.25" (133mm) width x 3" (76mm) depth.
• 漏斗: An aluminum funnel will assist in filling.
• 泥刀: A forged 钢 trowel will assist in filling.

Preparations Prior to Slump Test

在开始测试之前, 模具, base plate 和 all testing materials should be clean 和 free of any remnants of prior testing. The inside surface of both the base 和 模具 should be dampened before beginning the test to reduce surface friction.

Find a flat surface for testing 和 place 模具 on top of the base plate. This area should also be free from vibrations. The testing should only be performed on fresh, newly mixed concrete for best results.

混凝土坍落度试验 Procedure

1. Fill 模具 with fresh concrete in three layers (see images 1-3). Each layer should be tamped uniformly, 25 times using the rounded end 钢 rod

2. Once the cone is full, level the top by removing any excess concrete from the top of the cone.

3. Hold the h和les found at the base of 模具 和 carefully lift the cone vertically.

4. The resulting unsupported concrete will therefore slump 和 the decrease in height should be measured to the nearest 5mm (0.25英寸)在中心点.

解释坍落度测试结果

真正的衰退 – Here the general mass of the concrete drops evenly without any disintegration. This is the desired test result.
剪切衰退 – Here one side of the concrete shears or falls from the main portion of concrete. This is an indication that the concrete lacks cohesion.
崩溃衰退 – Here the concrete completely collapses. This is an indication that the mix is too wet.
零衰退 – Here the concrete maintains the shape of 模具. This type of concrete is too stiff 和 has almost no workability.

If shear slump, collapse slump or zero slump are found, the slump test should be repeated. If the second test also results in a failed slump test, then that batch of concrete should be rejected according to the established safety st和ards.

我们的 混凝土坍落度图 describes the applications for the various slump values that may be obtained from this testing.

坍落度的混凝土和易性

洪堡销售各种 坍落度测试设备 和 配件 for on-site or laboratory 衰退测试 of fresh concrete. Please contact the testing experts at 洪堡 with any questions about construction materials testing.

Photo courtesy of Build with Matt Risinger. 观看YouTube视频.