Astm c31 free pdf

The duration of vibration required will depend upon Usually sufficient vibration has been applied as soon purposes stated in 4. Fill the molds and storage. The supporting surface on which specimens are stored vibrate in the required number of approximately equal layers. If cylinders Place all the concrete for each layer in the mold before starting in the single use molds are moved, lift and support the vibration of that layer.

In compacting the specimen, insert the cylinders from the bottom of the molds with a large trowel or vibrator slowly and do not allow it to rest on the bottom or similar device. If the top surface is marred during movement to sides of the mold.

Slowly withdraw the vibrator so that no large place of initial storage, immediately refinish. When placing the final For concrete mixtures with a specified strength of than 3 in. Longer times may be required for lower slump concrete, but the vibration time should rarely have to exceed 10 s per psi [40 MPa] or greater, the initial curing temperature shall be insertion.

Various procedures are capable of being used during the initial curing period to 9. An per layer is given in Table 4. When more than one insertion per appropriate procedure or combination of procedures shall be layer is required distribute the insertion uniformly within each used Note 6. Shield all specimens from the direct sunlight layer.

Allow the vibrator to penetrate through the layer being and, if used, radiant heating devices. The storage temperature vibrated, and into the layer below, about 1 in. After shall be controlled by use of heating and cooling devices, as each layer is vibrated, tap the outsides of the mold at least 10 necessary. Record the temperature using a maximum-minimum times with the mallet, to close holes that remain and to release thermometer.

If cardboard molds are used, protect the outside entrapped air voids. Use an open hand to tap cardboard and surface of the molds from contact with wet burlap or other single-use metal molds that are susceptible to damage if tapped sources of water. For specimens wider than 6 in. Allow the shaft of the vibrator to structed wooden boxes or structures, 3 place in damp sand pits, 4 cover penetrate into the bottom layer about 1 in. After each with removable plastic lids, 5 place inside plastic bags, or 6 cover with layer is vibrated, tap the outsides of the mold sharply at least 10 plastic sheets or nonabsorbent plates if provisions are made to avoid times with the mallet to close holes left by vibrating and to drying and damp burlap is used inside the enclosure, but the burlap is release entrapped air voids.

A satisfactory tempera- ture environment can be controlled during the initial curing of the 9. Other suitable methods may be used provided the requirements 9.

For concrete mixtures with a specified strength of psi [40 MPa] or by striking them off with the tamping rod where the consis- greater, heat generated during the early ages may raise the temperature tency of the concrete permits or with a handheld float or trowel.

Immersion in water saturated with If desired, cap the top surface of freshly made cylinders with a calcium hydroxide may be the easiest method to maintain the required thin layer of stiff portland cement paste which is permitted to storage temperature. When specimens are to be immersed in water. Early-age curing treatment. On the other hand, at later ages, test results may be lower for higher initial storage temperatures.

At the end of the curing Remove all beam specimens within 30 min after removing the molds, cure specimens with from field storage and store in water saturated with calcium free water maintained on their surfaces at all times at a hydroxide at Observe the precautions of Specification C, except when capping with sulfur mortar given in When removal from curing to testing.

For a period not to exceed 3 h immediately prior to test, standard curing temperature is not Transportation of Specimens to Laboratory required provided free moisture is maintained on the cylinders See Note 8. During transporting, During cold weather, protect the saturated with calcium hydroxide at Drying of the surfaces of the Prevent moisture loss during transportation by wrapping the beam shall be prevented between removal from water storage specimens in plastic, wet burlap, by surrounding them with wet and completion of testing.

Transporta- NOTE 7—Relatively small amounts of surface drying of flexural speci- tion time shall not exceed 4 h. Report for the specimens made and cured as stated in 4. Protect all surfaces of the cylinders from the elements Provide the cylinders with the same temperature and moisture mens, environment as the structural work.

Test the specimens in the To meet these conditions, specimens made for the any deviations from referenced standard test methods, and purpose of determining when a structure is capable of being put For standard curing method, report in service shall be removed from the molds at the time of the initial curing method with maximum and minimum tem- removal of form work.

For field curing method, At the end of elements, temperature and moisture environment, and time of 48 6 4 h after molding, take the molded specimens to the removal from molds. Store specimens representing pavements of slabs on grade by placing them on Keywords the ground as molded, with their top surfaces up.

Bank the Approved October 1, Approved May 1, ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.

Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below.

Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phone , fax , or service astm. Permission rights to photocopy the standard may also be secured from the ASTM website www. The combined length of the vibrator shaft and vibrating element shall exceed the depth of the section being vibrated by at least 75 mm [3 in.

The vibrator frequency shall be checked periodically with a vibrating-reed tachometer or other suitable device. For placing concrete in a beam mold, either a shovel or scoop is permitted. NOTE 5—The modulus of rupture can be determined using different specimen sizes. However, measured modulus of rupture generally increases as specimen size decreases. Sampling Concrete 6. Testing Requirements 6. The number and size of cylinders cast shall be as directed by the specifier of the tests.

In addition, the length shall be twice the diameter and the cylinder diameter shall be at least 3 times the nominal maximum size of the coarse aggregate.

When the nominal maximum size of the coarse aggregate exceeds 50 mm [2 in. For acceptance testing for specified compressive strength, cylinders shall be by mm [6 by 12 in. NOTE 4—When molds in SI units are required and not available, equivalent inch-pound unit size mold should be permitted. The length shall be at least 50 mm [2 in. The ratio of width to depth as molded shall not exceed 1.

Unless otherwise specified by the specifier of tests, the standard beam shall be by mm [6 by 6 in. The same specimen size shall be used when comparing results and for mixture qualification and acceptance testing.

Minimum Cross-Sectional Dimension by mm [4 by 4 in. The concrete used in performing the air content test shall not be used in fabricating test specimens. NOTE 6—Some specifications may require the measurement of the unit weight of concrete. The volume of concrete produced per batch may be desired on some projects. Also, additional information on the air content measurements may be desired.

Leavitt, J. Molding Specimens 9. Determine the method of consolidation from Table 3, unless another method is specified. If the method of consolidation is rodding, determine molding requirements from Table 4. If the method of consolidation is vibration, determine molding requirements from Table 5. Select a scoop of the size described in 5. While placing the concrete in the mold, move the scoop around the perimeter of the mold opening to ensure an even distribution of the concrete with minimal segregation.

Each layer of concrete shall be consolidated as required. In placing the final layer, add an amount of concrete that will fill the mold after consolidation. After filling the mold, finish the cylinders in accordance with 9.

If the method of consolidation is rodding, determine the molding requirements from Table 4. If the method of consolidation is vibration, determine the molding requirements from Table 5. Determine the number of roddings per layer, one for each 14 cm2 [2 in. Select a placement tool as described in 5. Using the scoop or shovel, place the concrete in the mold to the height required for each layer. Place the concrete so that it is uniformly distributed within each layer with minimal segregation. Each layer shall be consolidated as required.

After filling the mold, finish the beams in accordance with 9. Rod each layer uniformly over the cross section with the rounded end of the rod using the required number of strokes.

Rod the bottom layer throughout its depth. In rodding this layer, use care not to damage the bottom of the mold. After each layer is rodded, tap the outsides of the mold lightly 10 to 15 times with the mallet to close any holes left by rodding and to release any large air bubbles that may have been trapped.

Use an open hand to tap cylinder molds that are susceptible to denting or other permanent distortion if tapped with a mallet. After tapping, spade each layer of the concrete along the sides and ends of beam molds with a trowel or other suitable tool.

Underfilled molds shall be adjusted with representative concrete during consolidation of the top layer. Overfilled molds shall have excess concrete removed. The duration of vibration required will depend upon the workability of the concrete and the effectiveness of the vibrator.

Usually sufficient vibration has been applied as soon as the surface of the concrete has become relatively smooth and large air bubbles cease to break through the top surface. Continue vibration only long enough to achieve proper consolidation of the concrete see Note 7. Fill the molds and vibrate in the required number of approximately equal layers.

Place all the concrete for each layer in the mold before starting vibration of that layer. In compacting the specimen, insert the vibrator slowly and do not allow it to rest on the bottom or sides of the mold. Slowly withdraw the vibrator so that no large air pockets are left in the specimen. Longer times may be required for lower slump concrete, but the vibration time should rarely have to exceed 10 s per insertion. Batch tickets contain a lot of useful information, like which mix design is being used on that pour and how long it has been since the truck left the plant.

It is recommended that concrete that has been out more than 90 minutes should not be used in a pour, because concrete will start to harden up and be very difficult to pour evenly. If you are making multiple sets of cylinders with more than one truck, write the number on the batch ticket and on your paperwork so you know which truck goes with which set of cylinders.

If you are also doing slump, temperature, and air content on this sample, note that you must have these cylinders made within 15 minutes of receiving the sample, so plan accordingly and set up your work area beforehand ASTM C Paragraph 4.

It helps to group your equipment by test, so you have everything you need for each test in one place. When you are picking a place to make your cylinders, make sure it is in a level area that is free of debris, away from vibration, and away from moving vehicles and large construction equipment. Be sure to write on your paperwork which location you are making or leaving your cylinders at, because someone else may be the one to come pick them up. If you are rodding the cylinders to consolidate them, the amount of layers will vary by sample size: 4x8 cylinders require 2 equally sized layers, and 6x12 cylinders require 3 equally sized layers.

All cylinders in a set should be started at the same time and have their layers added at the same time you do not add three layers for one and then move on to the next cylinder, they must all have their first layer added and rodded before you move on to layer 2. For both sizes, each layer will be rodded 25 times in an even pattern, distributing the holes uniformly over the cross-section of the mold.

The bottom layer must be penetrated to the bottom of the mold, and for the layers above it you must go through that layer and about an inch into the layer below it.

When you are doing the last layer, if your mold is underfilled you can add extra concrete to keep it properly filled as you rod. After you rod each layer you need to tap the outside of your mold with an open hand about 10 to 15 times plastic molds may be damaged if you use a mallet to let excess air out of the cylinder and close the holes from rodding ASTM C31 Paragraph 9.

If you are vibrating the cylinders to consolidate them, you will always have 2 equal layers to put into the mold, but for 4x8s you insert the vibrator one time per layer and for 6x12s you insert it twice per layer. You will know when the vibration is done when the surface of the concrete is relatively smooth and air bubbles have stopped coming up to the top surface.

After you have consolidated the concrete, you will need to strike off the concrete to provide a smooth surface. Use a back-and forth left-to-right sawing motion, starting in the middle and working away from you, then come back to the middle and move the strike-off bar towards you, still performing the same sawing motion.

If there are large holes in the end of the cylinder, your lab tech will have to grind it down or saw cut the end of the cylinder, so you want it to be smooth. Use your rag to clean around the rim of the mold, wiping away excess concrete from the edge but never touching the material inside the rim.

Label each cylinder mold with the project number, the date and time you made the cylinder, and the sample number. Knowing the time and date will be important for the lab tech to know when to break the cylinders. Having the right sample number and project will help the lab know which set is which, which can get confusing if there are many cylinders coming in at the same time, so please label them carefully!

Cover each cylinder with an appropriate sized cylinder bag and place it in a protected location free of vibration and disturbances. These cylinder transport racks can be secured to the bed of your truck or placed in a cooler to further protect them from extreme temperatures. Cylinders need to be picked up anywhere from 18 to 48 hours after they are made. Don't leave them out there for a week and forget about them or your lab tech is going to be very confused when they look for cylinders to break and find an empty moisture room.