Capillary suction test

Clarity Very poor Good Poor to good 

Settling rate Very slow Fair Fast 

Filtration rate Very low Fair Slow to fast 

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As an alternative to the filter test, the capillary suction test (CST) can give a more rapid, though potentially less accurate, assessment of filtration performance. Figure 3.11 shows a schematic of the apparatus required which essentially comprises a small reservoir and a relatively thick filter... 

The second approach to characterize wetting considers the ability of the fluid to penetrate a powder bed. It involves the measurement of the extent and rate of fluid rise by capillary suction into a column of powder, better known as the Washburn test. Considering the powder to consist of capillaries of radius R, the equilibrium height of rise he is determined by equating capillary and gravimetric pressures, or... 

A sorptivity test is normally carried out to measure capillary suction in concrete. 

In another study, Martinola et al. (2002) evaluated the water permeability of cracked and uncracked HPFRCC by water absorption test. In their study, the amount of water taken up by capillary suction was determined on cubes cut out from the middle section of the beams, which were subjected to a four-point bending test. Maximum crack width in the cracked HPFRCC specimens was found to be about 0.10 mm. Both cracked and uncracked HPFRCC exhibited very low water absorption coefficient in their study. 

This method relies on the capillary pressure created by edal fiher paper to suck filtrate from a slurry contained in a small cylindrical reservoir placed on the surface of the paper. It is believed to be equivalent to a constant-pressure filtration. A picture of a capillary suction time device is given in Figure 2.25, together with a schematic diagram of the test cell. 

Figure 2.25a Capillary suction time test-schematic of test cell...

Figure 2.25b Capillary suction time test equipment...

Extensive laboratory tests on electrochemical realkalization have been conducted at BAM Berlin (Mietz and Isecke, 1994 Mietz et al., 1994). It has been found that the realkalized zone around the rebar increases with time and current density, i.e. proportionately to the electric charge passed (Mietz et al., 1994). On the other hand the observed realkalization from the concrete surface is independent of current density and thus only due to capillary suction of... 

A test tube has a rounded bottom and is designed to hold and to heat small volumes of liquid. A Pasteur pipet is a small glass tube with a long thin capillary tip and a latex suction bulb. 

An improved method, utilizing a capillary Pasteur pipet for introducing the sample onto the chromatographic column approximately doubles the effectiveness (theoretical plates) of the column. Dry-column flash chromatography has been adapted for use in the instructional laboratory. The "column" consists of a dry bed of silica gel in a sintered glass funnel placed in a standard vacuum filtration flask the solvent is eluted by suction. Small (16 X 150-mm) test tubes inserted into the flask below the stem of the funnel are used to collect the fractions. This technique has been used successfully to separate mixtures ranging from 150 to 1000 mg. 

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