Posts

Air Content of Concrete by Volumetric Method (ASTM C - 173)

Image
 Air Content of Concrete by Volumetric Method ASTM C - 173 Introduction In this test, we will determine the air content in normal and heavy-weight concrete If the air content increases 1% above the design value  the strength reduction will be 3 to 5% Apparatus Air Meter, Bowl diameter equal to 1 to 1.25 times, Capacity of bowl 0.075 cubic feet, Top section 20% larger than a bowl Temping Rod,  Hemispherical tip, diameter 16 + 2 mm, height 100 mm greater than the bowl Isopropyl Alcohol, Calibrated Cup, Funnel, Rubber Syringe, Mallet, Procedure Dampen the bowl with water, fill the fresh concrete in the bowl with two equal layers First Layer, fill the half bowl of its volume, rodding 25 times through its depth, and distribute over the cross-section, 10 to 15 times tap with the mallet outside of the bowl Second Layer,  fill the remaining bowl, rodding 25 times to penetrate the previous layer about 25 mm, and distribute over the cross-section, 10 to 15 times tap with the mallet outside of
Post a Comment
Read more

Air Content of Concrete Pressure Method ( ASTM C - 231 )

Image
  Air Content of Concrete by Pressure Method ASTM C - 231 Introduction In this test, we will determine the air content in normal and heavy-weight concrete If the air content increases 1% above the design value  the strength reduction will be 3 to 5% Apparatus Meter Type A, Cover assembly fitted air valve, air bleeder valve, petcocks for bleeding off, main air valve Cylindrical Container,  Diameter equal to 0.75 to 1.25 times the height, capacity at least 0.2 cubic feet Temping Rod,  Hemispherical tip, diameter 16 + 2 mm, height 100 mm greater than the bowl Internal vibrator,  diameter 19 to 38 mm, frequency 7000 per min. Strike off Plate,  Thick 12 mm, length, and width 50 mm greater than the measure  Mallet,  600  +  200 grams Rubber Syringe Internal Vibrator or Temping Rod If the slump is greater than 75 mm, using a rod  If the slump is 25 to 75 mm, using the rod or vibrator If the slump is less than 25 mm, using a vibrator  Procedure of Temping Rod Dampen the container with water,
Post a Comment
Read more

Density, Yield and Air Content of Fresh Mix Concrete (ASTM C-138)

Image
 Density, Yield, and Air Content of Fresh Mix Concrete (ASTM C-138) Introduction In this test, we have to determine the density of fresh-mix concrete and give formulas for calculating the yield, cement content and air content of the concrete, Control the quality of concrete the density test is very important A lower density may indicate Material has changed lower specific gravity Change in the proportion of ingredients Higher air content Higher water content Lower cement content A higher density would be indicated the reverse of the above mentioned  Yield Yield is defined as the volume of the concrete produced from a mixture of known quantities of the component's materials Apparatus Measuring cylindrical container Temping rod, diameter 16 + 2 mm Internal vibrator, diameter 19 to 38 mm, frequency 7000 per min. Strike off Plate, Thick 12 mm, length, and width 50 mm greater than the measure  Mallet, 600 + 200 grams Internal Vibrator or Temping Rod If the slump is greater than 75
Post a Comment
Read more

Slump Test of Freshly Hydraulic Mix Concrete (ASTM C-143)

Image
 Slump Test of Freshly Hydraulic Mix Concrete (ASTM C-143) Introduction The slump test is to determine the consistency of concrete, water content increase or decrease the cause of slump increase or decrease Many other factors can change slump without changing in water content in concrete Such as aggregate properties, grading, mix proportion, air content, concrete temperature, or add mixture Apparatus Frustum Cone  Non-Absorbent Base Plate Temping Rod, Diameter 16 + 2 mm, Height 400 to 600 mm Measuring Device Procedure Dampen the cone and base plate and place it flat and free of vibration surface Clamp the cone with a base plate or technician standing of two-foot pieces Fill the slump cone in three layers of even concrete distribution: Fill the first layer from the bottom to 70 mm, Roding 25 times through its depth Fill the second layer from the first layer to 160 mm, Roding 25 times through the previous layer approximately 25 mm  Fill the third layer from the second layer to the to
Post a Comment
Read more

Making and Curing of Concrete Cubes (BS EN-12390 Part 2)

Image
  Making and Curing Concrete Cubes  (BS EN-12390 Part 2) Introduction This standard specifies a method for making and curing test specimens for strength test Apparatus Cubes Molds = L 6 x W 6 x H6 Internal Vibrator = minimum frequency 120 Hz, diameter not exceeding one-quarter Vibration Table = minimum frequency 40 Hz Compacting Bar = having a square cross-section of approximately 25 by 25mm and a length of approximately 380mm Mallet Procedure Remix the sample before filling the cube molds Before filling the concrete, covered the mold's inner surface with a thin film of non-reactive release material  Specimen compacted minimum of two layers, but no layer more than 100 mm in thickness Mechanical vibration or hand compaction Mechanical Vibration Vibrate the concrete until the all entrapped air remove from the concrete and the depression left from the surface of a concrete over-vibration is the cause of segregation Hand Compaction The first layer, distribute the strokes in uniform man
Post a Comment
Read more

Obtain Drill Cores & Sawed Beams of Concrete | ACI Level II – ASTM – C 42

Image
Obtain Drill Cores & Sawed Beams of Concrete ACI Level II – ASTM – C 42 Introduction This test method provides standardized procedure for obtaining and testing specimens to determine the compressive, splitting tensile and flexural strength of in–place concrete Generally test specimens are obtained when doubt exist concrete quality General Sampling Sample of hardened concrete for use in the preparation of strength test should not be removed before it is 14 days old Sample that have been damaged during removal shall not be used unless the damaged portion are removed Specimens containing embedded reinforcement shall not be used for determining compressive, splitting tensile & flexural strength A core specimens shall be drilled perpendicular to the surface and not near formed joint Measuring the Length of Drilled Cores Cores for determining the thickness of pavement slabs, walls & other structural elements shall have diameter of at least 95mm The lengths of such cores are stipu
Post a Comment
Read more