Concrete cylinder mould is made of plastic.
C228
Cylinder Mould, Ø 150x300 mm with upper and lower reinforced bands.
Weight: 2150 g approx.
C228-01
Cylinder Mould, Ø 100x200 mm with reinforced bands.
Weight: 920 g approx.
C229
Cylinder Mould, Ø 160x320 mm with upper and lower reinforced bands.
Weight: 2200 g approx.
How To Make and Cure Cylinders?
Equipment needed at the job site:
• Molds for casting cylinder specimens. Plastic molds are most common.
• Tamping rod with hemispherical tip 15 mm diameter for 150x300 mm cylinders or 10 mm diameter for 100x200 mm cylinders, or a vibrator
• Rubber or rawhide mallet, 0.6 ± 0.2 kg
• Shovel, hand-held wooden float, and scoop,
• Wheelbarrow or other appropriate sample container,
• Water tank or curing box with provisions to maintain required curing environment during initial curing period.
• Safety equipment as appropriate to handle freshly mixed con- crete.
Sampling concrete from a ready mixed concrete truck:
It is very important to obtain a sample of concrete that is repre- sentative of the concrete in the truck mixer. Sampling from con- crete delivery units should be conducted in accordance with ASTM C172 Standard Practice for Sampling Freshly Mixed Concrete. Concrete should be sampled from the middle of the load. The first or last discharge from the load will not provide a representative sample. The concrete must be sampled by diverting the chute into a wheelbarrow so that the entire discharge stream is collected. At least two portions during discharge are necessary to obtain a com- posite sample. The time elapsed between the first and final por- tion of the composite sample must not exceed 15 minutes. The minimum required size of the concrete sample is 28 L.
Prior to Casting Cylinders:
Cover the sample with a plastic sheet to protect the concrete from evaporation, sunlight, and contamination. Move the sample to the location where the fresh concrete tests are to be conducted. The testing location should be close to where the cylinders will be stored undisturbed for the initial curing period. After the concrete is transported to the location for casting the cylinders, remix the concrete in the wheelbarrow. Begin the slump, density (unit weight), and air content tests within 5 minutes and start molding cylinders within 15 minutes after the sample was obtained.
Casting the Test Cylinders:
• Label the outside of the mold with the appropriate identifica- tion mark. Do not label the lids or tops.
• Place the cylinder molds on a level surface
• Determine the method of consolidation
1. For concrete with slump less than 25 mm, con- crete should be consolidated by vibration
2. For concrete with slump 25 mm or higher, either rodding or vibrating is permitted.
• Determine the number of layers of concrete to be placed in the mold
1. For concrete to be consolidated with the tamping rod, place concrete in 3 equal layers for 150x300 mm cylinders; and in 2 equal layers for 100x200 mm cylinders
2. For concrete to be consolidated by vibration, fill the mold in two equal layers.
• Place the concrete in the mold by distributing it around the inside of the mold with the scoop. Consolidate the layer by rodding 25 times evenly distributed around the layer. When using a vibrator, insert it long enough so the surface is smooth and large air pockets ceases to break through to the top. Two insertions of the vibrator are required for a 150x300 mm and one insertion is required for a 100x200 mm cylinders. Avoid over vibration.
• Tap the sides of the mold 10-15 times with the mallet after each layer in order to close any insertion holes formed either by the rod or the vibrator.
• Strike off the top with a wooden float to produce a flat, even and level surface and cover with a plastic lid or a plastic bag.
Storing and transporting test cylinders:
• Move cylinder molds with fresh concrete very carefully by supporting the bottom
Place the cylinders on a flat surface in a controlled environment where the temperature is maintained in the range of 16 to 270C. When the specified strength of the concrete is greater than 40 MPa, the temperature range for initial curing should be maintained in the range of 20 to 260C. Immersing cylinders, completely cov- ered in water is an acceptable and preferred procedure that ensures more reliable strength results. Temperature in storage, such as in curing boxes, should be controlled using heating and cooling devices as necessary. The maximum and minimum tem- perature during initial curing should be recorded and reported.
• Protect cylinders from direct sunlight or radiant heat and from freezing temperatures in winter.
• Cylinders must be transported back to the laboratory within 48 hours of casting. Some concrete mixtures may take longer to set and these specimens may be transported at a later time. In any event cylinders should not be moved or transported until at least 8 hours after final set. Store cylinders to prevent damage and maintain moisture during transportation. Travel time from the jobsite to the laboratory should not exceed 4 hours.