6505-6 - 1 batching of ingredients mixing fresh concrete...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 batching of ingredients mixing fresh concrete placing & curing hardened concrete PRODUCTION OF CONCRETE Properties of Fresh Concrete Desirable characteristic: a) ease of transport and placement b) resistance to bleeding and segregation Consistency - describes the ease of flow of the fresh concrete. Cohesiveness - describes the water holding capacity (or resistance to bleeding) and the coarse-aggregate holding capacity (or resistance to segregation) of the fresh concrete. Workability - describes the composite property of both consistency and cohesiveness of the fresh concrete. (1) Slump Test (ASTM C 143) - A consistency test for fresh concrete. Procedure: (1) Fill the cone mold 1/3 full by volume ( 2 3/8 inches in height). (2) Rod 25 times uniformly. Cone Mold: Height = 12 inches. Base diameter = 8 inches. Top diameter = 4 inches. 2 Slump Test Procedure (Continued) (3) Fill cone 2/3 full by volume (6 1/8 inches in height). (4) Rod 25 times uniformly, just penetrating into previous layer. Slump Test Procedure (Continued) (5) Fill cone to overflowing. (6) Rod 25 times, just penetrating into the second layer. Slump Test Procedure (Continued) (7) Strike off excess concrete with rod. (8) Clean the overflow away from the base of the cone mold. 3 Slump Test Procedure (Continued) (9) Lift the cone mold up vertically in 5 2 seconds. Slump Test Procedure (Continued) (10) Measure the slump to the nearest 1/4 inch. Slump * The slump test is also used for controlling the uniformity of ready-mixed concrete. (2) Ball Penetration Test (ASTM C 360) Ball Penetration Procedure: Lower the weight of the ball penetration apparatus to the concrete surface slowly. Read the penetration to the nearest 1/4 inch after the weight has come to a rest. Ball + handle weighs 30 lbs. 4 Ball Penetration Test (3) Vebe Test A consistency test for stiff fresh concrete with a slump of zero or close to zero. Developed by Swedish engineer, V. Bahrner. Standardized in ACI Standard 211.3 . A similar test for determining the consistency of roller compacted concrete is standardized in ASTM C 1170 . Basic procedure : A slump cone is placed in a cylindrical mold, which is secured to a Vebe (vibrating) table. Fill the cone with concrete and remove the cone. A disk which is attached to a free moving rod is brought into position on top of the concrete cone, and the vibrating table is turned on. Measure and report the time required to mold the concrete from the conical to the cylindrical shape. Vebe Test Apparatus 5 Vebe Test Method A With 50 lb surcharge Method B Without surcharge Compacting Factor Test Apparatus (4) Compacting Factor Test Measures the compactibility of a fresh concrete ....
View Full Document

This note was uploaded on 05/26/2011 for the course CGN 6505 taught by Professor Mang during the Spring '11 term at University of Florida.

Page1 / 29

6505-6 - 1 batching of ingredients mixing fresh concrete...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online