Slump tests

Model Plasters. Model plaster should have a setting time of approximately 10 minutes. The fineness of the powder should be such that 98% passes a number 100 sieve (ca 0.15 mm) and 90% passes a number 200 sieve (ca 0.07 mm). Setting expansion should be less than 0.30%, compressive strength at the end of one h should be a minimum of 8.8 MPa (1276 psi), and the consistency should form a disk during the slump test of 30 2 mm diameter. 

Dental stone is generally used at a water—powder volume ratio of about 30 parts water to 100 parts of stone. The mix is not easily poured, but can flow readily under mechanical vibration. The physical property requirements include a setting time of 10 3 min fineness of powder, where 98% should pass a number 100 sieve (ca 0.15 mm) and 90% pass a number 200 sieve (ca 0.07 mm) linear setting expansion at 2 h of <0.20% compressive strength at 1 h of 20.6 MPa (2987 psi) and consistency such that the slump test disk is 30 2 mm diameter. 

Mixes of improved dental stone (type IV) using 22 parts of water to 100 parts of powder produce a mass that is not fluid and pourable but can be easily vibrated into place. The physical properties of the improved dental stone include a setting time 10 3 min, fineness of powder such that 98% passes a 100 sieve (ca 0.15 mm) and 90% passes a 200 sieve (ca 0.07 mm) setting expansion at 2 h limited to a max of 0.10% compressive strength at 1 h of at least 34.3 MPa (4974 psi) and a disk formed in the slump test for consistency of a 30 2 mm diameter. 

Fig. 2.17 Slump tests after various intervals of time for concrete incorporating 3% SMF by weight of cement (Mailvaganam). 

Concretes containing VEAs have consistencies that are structured while static but become highly flowable, with self-leveling characteristics, when work is imparted to it. Data presented in Fig. 7.28 show that medium-strength concretes with equal slumps perform very differently in the washout test. This indicates that the slump test does not correlate to washout... 

When the concrete gets to the site, before it is placed, demand to see a slump test. If it is greater than 4 in., unless a higher slump is specifically approved by the materials manufacturer, stop the job and tell the contractor to remove the concrete from the site as unacceptable. 

Except for the CMUs which were produced in an industrial block plant, the batches were completed following the same procedure. Before starting a typical concrete batch, the water, sand and pea gravel were adjusted for moisture content. The two aggregates and the plastic filler were introduced into the mixer and mixed for approximately 30 seconds. The cement and two-thirds of the total water were added and the drum was rotated for 2 minutes more. The rest of the water was added within the next 30 seconds. After two minutes the drum was stopped, and the slump test was performed. The drum was then scraped to loosen any material not previously mixed. It was restarted and rotated... 

Figure 1 presents the slump test data of mix No. 2. The figure indicates that one percent of plastic generally did not change significantly the workability of fresh concrete. When the plastic content was increased to 4 percent, the slump decreased in all cases except for the batch with PET. 

NO-SLUMP GROUT Grout with a slump of lin. (25 mm) or less according to the standard slump test (ASTM C 143). See SLUMP, SLUMP TEST. 

Measurement of workability. Since workabiHty of concrete is a combination of properties (fluidity, cohesion, and compactabiHty), there are several standardised tests that measure one or more of these properties. These tests are based on measuring the behaviour of fresh concrete subjected to a standardised procedure. The most commonly used is the slump test. Fresh concrete is placed in the apparatus shown in Figure 12.1, following a standardised procedure then, the mould is removed, and the concrete will slump under its own weight. The decrease in height measured with respect to the initial height is taken as a measure of the workabihty of concrete. 

In general, results of different types of tests are not correlated. Compared with the slump test, flow tests are more suitable for flowable concrete, while the compacting... 

F ie 12.1 Slump test form measurement of workability of fresh concrete... 

Table 12.2 Classes of consistence of concrete measured with slump test, vebe test, degree of compactability and flow table test [3]...

Spread/slump test 8.6 Deposit three dots of adhesive 0.65 mm in diameter and 0.25 mm thick on two glass slides. Maintain sample 1 at 25 5 °C and 50 + 25% RH. Cure sample 1 per vendor instmction. <10% increase in dot size is acceptable... 

South African National Standards. SANS 5862-1 2006, Concrete tests - consistency of freshly mixed concrete - slump test. South African National Standard. Standards South Africa. Pretoria, Gauteng, Republic of South Africa (2006). 

Table 14.1 summarizes the test results of the laboratory study,in which each data point represents the average from about 10 specimens. The workability of the fresh conaete was measured by a slump test in accordance with ASTM C 143-90a. Good workability (180 to 230 mm slump) was observed for mixes with up to 1.8 kg/m of waste fibers. The slump decreases to 70 mm for 5.95 kg/m 51 mm... 

Slump Test. (1) A rough test for the consistency of freshly mixed concrete in terms of the subsidence of a truncated cone of concrete when upturned from a bucket ASTM - C143 and B.S. 1881. 

A works test for the consistency of vitreous enamel slip for details see IRWIN SLUMP TEST. 

Vebe Apparatus. A device developed by the Swedish Cement Association for the measurement of the consistency of concrete. It is a slump test in which the consistency is expressed in degrees, the value being obtained by multiplying the ratio of the volume of the test-piece after vibration to that before vibration by the number of vibrations required to cause the test-piece to settle. 

The flow of the paste and concrete mixes was measured using a flow table (BS EN 12350-5 2000 [15]) and a slump test. 

As measures of workability of the fresh mix, several different tests are proposed, but each of them gives a certain indication which is not comparable with the others. The slump test (Abrams cone) and the Vebe test give only single values by which the mix is characterized, in millimeters and seconds, respectively. Therefore, nothing more complicated than the Newton model is used and the test results do not characterize the mix without ambiguity. However, these and other similar one-point tests are used frequently, mainly for their simplicity and, in most cases, acceptable repeatability of results. The required workability is expressed as minimum slump, maximum Vebe time, or any other measure, and in many cases such a simple result is sufficient however, it is necessary to understand its limitations. In certain compositions the results are ambiguous or even impossible to execute very stiff mixes cannot be tested simply and compared with valid results the same concerns very fluid mixes with superplasticizers. 

Special measures of workability may be necessary when improved resistance to segregation is required for special reasons. Estimation by eye given by an experienced practitioner is also valid. The relation between Bingham model parameters and slump test results has been studied by Wallevik (2006) who has shown that the slump may be, to some extent, predicted from the yield... 

IPC-A-20/21 Stencil Pattern for Solder Paste Slump Test IPC-A-24 Flux/Board Interaction Board IPC-A-36 CFC Cleaning Alternatives Artwork IPC-A-38 Fine Line Roimd Robin Test Pattern IPC-A-48 Surface Mount Airforce Mantech Artwork IPC-A-600 Acceptability of Printed Boards IPC-A-610 Acceptability of Printed Board Assemblies... 

How are concrete truck deliveries supervised for timing, quality (slump test) and traceability to the delivery ticket ... 

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