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Concrete Mix Design
Published in M. Rashad Islam, Civil Engineering Materials, 2020
The concrete slump test measures the consistency of fresh concrete before it sets. It is performed to check the workability of freshly mixed concrete, and therefore, the ease with which the concrete flows. It can also be used as an indicator of an improperly mixed batch. The test is popular due to the simplicity of the involved apparatus and procedure. The slump test is used to ensure uniformity for different loads of concrete under field conditions. The test is carried out using a metal conical frustum mold, known as the slump cone or the Abrams cone. It is open at both ends, and has handles as shown in Figure 4.3. The cone has an internal diameter of 4.0 in. (100 mm) at the top and of 8.0 in. (200 mm) at the bottom, with a height of 12 in. (300 mm). The cone is placed on a hard, flat surface. This cone is filled with fresh concrete in three layers. Each layer is tamped 25 times with a 2 ft (600 mm)-long metal rod, measuring 5/8 in. (16 mm) in diameter. At the end of the third stage, the concrete is struck off at the top of the mold. The mold is carefully lifted vertically upward, so as not to disturb the freshly compacted concrete cone.
Flocculant effects on fluidity and strength behavior of cemented dredged clay with high water content
Published in Marine Georesources & Geotechnology, 2021
Gui-Zhong Xu, Cheng-Chun Qiu, Miao-Miao Song, Yu-Peng Cao, Jie- Yin
The fluidity is usually used to describe the flow characteristics of soils, which is an important quality control index for designing beneficial reuse of dredged clay. The apparatus of concrete slump test is not suitable for determining the fluidity of dredged clay and freshly mixed cemented-dredged clay with high water content (Lee 2004). Hence, the flow tests were conducted according to the JHS A 313 flow test standard (Japan Highway Public Corporation 1992). The fluidity determined using this method has been used in many land reclamation projects using the cemented dredged clay as fill materials, including the Central Japan International Airport Construction (Kitazume and Satoh 2005), the Kumamoto Port (Satoh et al. 2001), etc. The special plexiglass cylinder with both diameter and height of 80 mm (Figure 2), were used to measure the fluidity. In the testing process, the cylinder was first placed in the center of the plexiglass plate, and the mixtures were quickly and uniformly poured into the cylinder. Then the cylinder was lifted vertically and the maximum diameter in two perpendicular directions after spreading freely for 1 minute, was measured. Each flow test was conducted thrice in parallel. The fluidity is equal to the average of the maximum and minimum values of the measured maximum diameter. All the flow texts were completed in two minutes.