Self consolidating concrete slump test astm, kommentare
A VSI of 0 or 1 indicates a stable mix, while a 2 or 3 is unstable. Recently, pads with a printed inch circle have been developed to make this test easier. The primary test used in the field for SCC is slump flow, although there are other fields tests currently in use.
Typical SCC mixes have slump flows ranging from 18 to 30 inches. The slump flow test is run both with and without the J-Ring in place and the passing ability is the craigslist lexington va personals dating in slump flow.
J-ring—The J-Ring is a measure of the concrete's passing ability—how easily it flows through obstructions and reinforcing.
ASTM C 1611-Standard Test Method for Slump Flow of Self-Consolidating Concrete
The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. The resistance to segregation is observed through a visual stability index VSI.
The technician observes the concrete as it spreads out in the slump flow test. This self consolidating concrete slump test astm promises to provide a quantitative value for segregation potential.
Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.
The U- box, L-box and J-ring tests measure the passing ability of concrete in congested reinforcement.
Here is a brief description of each—more information can be found in the appropriate ASTM test method. These notes and footnotes excluding those in tables and figures shall not be considered as requirements of the standard. A lower T20 T50 value may be appropriate for concrete that has to travel long horizontal distances without much obstruction.
Segregation probe—Not yet standardized, this test measures segregation by placing a thin wire ring atop the SCC and measuring how far it sinks into the concrete in two minutes. Appendix X1 provides a non-mandatory procedure that may be used to provide an indication of relative viscosity of self-consolidating concrete mixtures.
When the cone is lifted, the SCC spreads out like pancake batter. A difference greater than 2 inches indicates poor passing ability. Bill Palmer The T20 test measures viscosity by timing how many seconds it takes for the concrete to spread to 20 inches in diameter.
Combining values from the two systems may result in non-conformance with the standard. The J-ring test is a variation to the slump flow, where a simulated rebar cage is placed around the slump cone and the ability of the SCC mix to spread past the cage without segregation is evaluated.
The slump flow is measured as the diameter of the pancake. The slump cone is completely filled without consolidation, the cone lifted, and the spread of the concrete measured.
Slump Flow Test of Self-Consolidating Concrete (SCC) - ASTM C - Video Dargoole
During the slump flow test, the viscosity of the SCC mixture can be estimated by measuring the time taken for the concrete to reach a spread diameter of 20 inches mm from the moment the slump cone is lifted up. T20 or T50 test-This is a measure of the concrete's viscosity and is measured as the amount of time it takes for concrete in the slump flow test to reach a diameter of 20 inches or 50 centimeters.
The VSI is established based on whether bleed water is observed at the leading edge of the spreading concrete, or if aggregates pile at the center.
ASTM A slump flow test is often performed with the slum cone upside down. Therefore, this test method is considered applicable to self-consolidating concrete having coarse aggregate up to 25 mm [1 in.
A higher T20 T50 value indicates a more viscous mix which is more appropriate for concrete in applications with congested reinforcement or in deep sections. Another test being standardized is a column test, which measures the coarse aggregate content of concrete at different heights in a placed columnar specimen as an indication of stability or resistance to segregation.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Thanks to our Website Sponsors Testing Several test procedures have been successfully employed to measure the plastic properties of Self-Consolidating Concrete. A number from 0 to 3 is assigned—0 for no segregation to 3 for obvious segregation and paste separation cement, water, and fines from the concrete matrix.
The spread can range from 18 to 32 inches to mm. The slump flow test, using the traditional slump cone, is the most common field test and is in the process of being standardized by ASTM.
Slump Flow Test of Self-Consolidating Concrete (SCC) - ASTM C1611
Thanks to Euclid Chemical for this video segment. A T20 between 2 and 5 seconds is taken as a low viscosity concrete.
The U-Box and L-Box tests are used for product development or prequalification and involve filling concrete on one side of the box and then opening a gate to allow the concrete to flow through the opening containing rebar.
Appendix X1 provides non-mandatory visual rating criteria that may be used to classify the ability of a self-consolidating concrete mixture to resist segregation stability.