JIS-A-1128-1975-ENG.pdf

is japanese industrial standard method of test fur air content of fresh concrete by pressure method jis a 1 128 - 1 9 7 5 translated and published by japanese standards association printed in japan copyright japanese standards association provided by ihs under license with jsalicensee=ihs employees/1111111001, user=wing, bernie not for resale, 03/10/2007 19:13:36 mstno reproduction or networking permitted without license from ihs -,-,- translation without guarantee in the event of any doubt arising, the original standard in japanese is to be evidence a 1128-1975 edition 1 japanese text established by minister of international trade and industry date of establishment: 1960-03-01 date of revision: 1975-02-10 date of public notice in official gazette: investigated by: 1975-02-20 japanese industrial standards committee technical committee on concrete divisional council on civil engineering- construction this english translation is published by: japanese standards association 1-24, akasaka 4, minato-ku tokyo 107 japan 0 jsa, 1975 copyright japanese standards association provided by ihs under license with jsalicensee=ihs employees/1111111001, user=wing, bernie not for resale, 03/10/2007 19:13:36 mstno reproduction or networking permitted without license from ihs -,-,- udc 666.972.05:620.168.4 japanese industrial standard j i s method of test for air content of fresh concrete by pressure method a 1128-1975 i , scope this japanese industrial standard covers the test for determining the air content of fresh concrete by pressure reduction (i). i note ( 1 this test method is suitable for concrete o r mortar using common aggregate, but is unsuitable for concrete o r mortar using porous aggregate such as artifical light-weight aggregate, aggregate correction factor of which cannot be determined accurately. remark: the principle of this test is based on boyles law. 2. test apparatus the test apparatus shall be as indicated in fig. i . fig. 1 exhaust port pressure gauge initial pressure / chamber shows the condition where the pressure in the air chamber is increased to the fixed pressure. (the gauge needle points the initial pressure .) shows the condition where a pressure is applied to concrete by opening the actuating valve. (the gauge needle points an apparent air content of concrete.) applicable standards: jis a 11 15-method of sampling fresh concrete jis a i l 16-method of test for unit weight and air content (gravimetric) of fresh concrete jis a 1 138-method of making test sample of concrete in the laboratory jis a 861 o-internal vibrators for concrete copyright japanese standards association provided by ihs under license with jsalicensee=ihs employees/1111111001, user=wing, bernie not for resale, 03/10/2007 19:13:36 mstno reproduction or networking permitted without license from ihs -,-,- 2. i the construction of the test apparatus shall be such that the test will be conducted by pouring water into the space between the cover and concrete as indicated in fig. i . remark: a test apparatus so constructed as to conduct the test without pouring water may be used. 2.2 adequate strength. depth. smoothly be machined. maximum size of coarse aggregate as shown in table i . the container shall be a metal cylinder with a flange, watertightness, and the interior surface of the container and the upper surface of its flange shall the diameter of the container shall be approximately equal to its the container shall have a minimum capacity conforming to the table 1 max. size of coarse aggregate min. capacity of container mm i 50 o r less 6 80 or less 12 2.3 the cover shall have a flange, watertightness, and adequate strength, and shall be equipped with an exhaust port and water pouring port. and the surfaces of its flange shall be especially smoothed by machining. the underside of the cover, remark: the test apparatus so constructed as to conduct the test without pouring water shall be such as allowing a spout o r the like to be inserted through the exhaust port, 2.4 the air chamber attached to the top of the cover shall have an inside capacity of approximately 5% of that of the container. pressure regulating valve, and shall be connected with the pressure gauge and a hand pump (not shown in fig. i). assembling the cover and container so that high pressure air in the air chamber may be jetted into the container as required. to allow no water to enter the air chamber. the air chamber shall be equipped with a the actuating valve shall be installed on the cover after the actuating valve shall be so constructed as the construction of the cover and container shall be such that they, when assembled, will not allow water and air to leak at a pressure of 1 kgf/cm2 (98.1 kpa). remark: in this standard, the units and values in parentheses are ones used in the international system of units (si), and shown together as reference. the pressure gauge shall have sensitivity of 0.01 kgf/cm2 (0.98 kpa) or so 2.5 for a capacity of approximately i kgf/cm2 (98.1 kpa). diameter, and shall have a graduation expressed in percentage of air content at pressure points corresponding to air content in the container, and a line clearly indicating the initial pressure (see section 4.2). its dial shall be 9 cm o r more in 2.6 for calibration of the unit, a device shall be prepared for easy removal of a required amount of water from the test apparatus. 2.7 the vibrator to be used shall be as specified in jis a 8610. 3. sample the method of sampling of concrete shall be as specified in jis a 11 15, or the sample shall be made in accordance with jis a 1 138. copyright japanese standards association provided by ihs under license with jsalicensee=ihs employees/1111111001, user=wing, bernie not for resale, 03/10/2007 19:13:36 mstno reproduction or networking permitted without license from ihs -,-,- jis a*i1228 75 4933608 0000252 7 3 a 1128-1975 4. calibration of test apparatus 4. i calibration of container fill the container fully with water, and weigh the in filling up, lightly apply cup grease along the flange, weight * of water required. place a polished glass plate on the flange, and then accurately fill the container with water by carefully moving the glass plate along the flange so as not to leave air bubbles. the weight of the required water shall be weighed with a scale which is sensitive to a weight less than o. 1% of the weight of the container and water. note* for the purpose of this standard, “weight“ means mass. 4.2 determination of initial pressure 4.2.1 after filling the container with water, prepare the top and back sides of the cover for ventilation, then carefully install the cover onto the container (2). installing the cover, pour water until air trapped between the back side of the cover and the water level is discharged. after 2 note ( ) the device for calibration (see section 2.6) so constructed as to be installed on the cover shail be installed on the cover at this stage. where water is not poured, the water level in the container shall accurately be flush with the top surface of the container: remark: 4.2.2 close all the valves, and operate the hand pump to make the pressure in the air chamber slightly exceed the initial pressure. gradually open the regulating valve to have the needle of the pressure gauge accurately points the initial pressure line. after approximately 5 seconds, 4.2.3 fully open the actuating valve, read the pressure gauga by equalizing the pressure in the air chamber to the pressure above the water level in the container, and note if the reading obtained accurately conform to the zero % graduation of air content. if not, check for leakage of water and air, and other defects, then repeat the calibration procedure. when the gauge needle indicates the same point deviating from the zero point after repeating the calibration procedure a few times, move the initial pressure line to a position so that the gauge needle will lie on the zero point. procedure to check the correctness of the relocation of the initial pressure line. after that , repeat the fig. 2 initial pressure copyright japanese standards association provided by ihs under license with jsalicensee=ihs employees/1111111001, user=wing, bernie not for resale, 03/10/2007 19:13:36 mstno reproduction or networking permitted without license from ihs -,-,- j i s a*ll28 75 4933608 0000253 9 = 4 a 1128-1975 4.3 calibration of graduation of air content 4.3.1 the same operation with that of section 4.2.1 shall be performed. using the device described in section 2.6, transfer a suitable amount of water from the container into the glass graduate, and indicate it in % of the capacity of the container. equalize the air pressure in the container with atmospheric pressure, close up the unit, then increase the air pressure in the air chamber to the initial pressure. the actuating valve to lead the high pressure air into the container, and after wating for the pressure gauge needle stabilized, read the graduation of air content. open 4.3.2 again transfer water from the container into the glass graduate in accordance with section 4.3. i , and indicate the total amount of the collected water in % of the capacity of the container, 4.3.1. read the graduation of air content as described in section 4.3.3 repeat the above operations several times, and compare the percentage of the collected water with the graduation of air content. if they coincide, the graduation of air content is correct. if not , make a diagram showing the relation between them to u s e it for the calibration of air content. remark: readings of the pressure gauge shall be taken after lightly tapping the gauge with the fingers. 5. measurement of aggregate correction factor 5. i the weight of fine and coarse aggregates contained in the sample concrete of the volume v to be tested for obtaining the air content in it shall be calculated by the f oll0 wing form ula: v 1cc = _ x wc b where, tul : weight of fine aggregate in the sample concrete of volume v : volume of the sample concrete (equals to the capacity of the container) ( z ) b : completed volume of concrete of one batch ( i ) wf : weight of fine aggregate used in one batch (kg) mjc : weight of coarse aggregate in the sample concrete of volume v (kg) lvc : weight of coarse aggregate used in one batch (kg) v (kg) 5.2 typical samples of fine aggregate and coarse aggregate, llj and zuc in weight respectively, shall be collected. separately immersed in water (3) to malre the moisture condition of the sample aggregate particles equivalent to that of the aggregate particles in the sample concrete. the sample fine and coarse aggregates shall be feed the sample aggregates into the container approximately one third filled with water. in feeding, a scoopful of the fine aggregate shall be put in the container to be followed by two scoops of the coarse aggregate, and this sequence shall be repeated. caution shall be taken to assure that the amount of air entering with the aggregates is minimized, and that all the aggregates are completely immersed. shall be removed quickly. and whenever the fine aggregate is added, the tamping rod shall be plunged approximately ten times into it to a depth of 25 mm o r so, emerging air bubbles to release air, the side of the container shall be tapped, 3 note ( ) five minutes o r so will be appropriate for the immersion period. copyright japanese standards association provided by ihs under license with jsalicensee=ihs employees/1111111001, user=wing, bernie not for resale, 03/10/2007 19:13:36 mstno reproduction or networking permitted without license from ihs -,-,- j i s a*1128 75 y933608 0000254 o w 5. a i 128-1975 5.3 after putting all the aggregates in the container, remove all bubbles on the surface of the water, cleanly wipe the flanges of the container and cover, insert the rubber packing between the flanges, and then clamp the cover onto the container. read the graduation of air content on the pressure gauge (4) by taking the steps described in section 6.3. this reading shall be used as aggregate correction factor g . 4 note ( ) if necessary, this reading shall be compensated in accordance with section 4.3.3, 6. measurement of air content of concrete 6 1 place the sample in the container to a depth approximately one third of the container, and level the surface. evenly plunge the tamping rod into the sample approximately 25 times, the rod when the capacity of the container is 7 liters or so. container 10 to 15 times with a wooden hammer so that the plunged holes and large bubbles on the surface disappear. thirds of the container, and repeat the leveling, plunging and tapping operations as described above. container, repeat the plunging and tapping operations, and level the surface by removing excessive sample with a metal rule. take caution so as not to hit the bottom of the container with then tap the side of the next, add the sample to a depth approximately two lastly, put the sample to the extent that it overflows a little the the plunging depth of the tamping rod shall approximately be equal to the thickness of each layer of the sample. 6.2 where vibration compaction by a vibrator is made, it shall conform to section 4.2 of je a 1116. remark: where water is not poured, the surface of the sample shall be on a level with the top surface of the container with a speciall