S.I. No. 162/1949 - Standard Specification (Portland Cement) Order, 1949.

S.I. No. 162 of 1949.

STANDARD SPECIFICATION (PORTLAND CEMENT) ORDER, 1949.

I, DANIEL MORRISSEY, Minister for Industry and Commerce, in exercise of the power conferred on me by subsection (3) of section 20 of the Industrial Research and Standards Act, 1946 (No. 25 of 1946), hereby order as follows :—

1. This Order may be cited as the Standard Specification (Portland Cement) Order, 1949.

2.—(1) The specification set forth in Part II of the Schedule to this Order is hereby declared to be the standard specification for the commodity described in Part I of the said Schedule.

(2) The said standard specification may be cited as Irish Standard 1 : 1949.

SCHEDULE.

PART I.

PORTLAND CEMENT

PART II.

SPECIFICATION.

In this specification " B.S. 410 : 1943 " means the British Standard of the serial number 410 published by the British Standards Institution in the year 1943.

COMPOSITION AND MANUFACTURE.

1. Portland Cement is manufactured by burning to incipient fusion an intimate and properly proportioned mixture consisting essentially of carbonate of lime, silica, alumina and oxide of iron, and by grinding the resultant clinker to a fine powder. It should contain no additions subsequent to burning other than water or calcium sulphate or both.

TESTS.

2. The cement shall comply with the following chemical and physical requirements. The details of the methods to be employed in testing and descriptions of the apparatus are set out in the Appendices.

With the exception of the tests for chemical composition, all the tests and the operations connected therewith shall be conducted at a temperature between 58° and 64° F. (14·4° and 17·8° C.). The same temperature limits shall apply to all water used in connection with the tests.

(a) Chemical Composition.

The percentage of lime (CaO), after deduction of that necessary to combine with the sulphur trioxide (SO₃) present, shall be not more than 2·8 times the percentage of silica (SiO₂) plus 1·2 times the percentage of alumina (Al₂O₃), plus 0·65 times the percentage of iron oxide (Fe₂O₃), nor be less than two-thirds of that amount. The ratio of the percentage of iron oxide to that of alumina shall not exceed 1·5. The weight of insoluble residue shall not exceed 1 per cent., that of magnesia (MgO) shall not exceed 4 per cent., and the total sulphur content calculated as sulphur trioxide shall not exceed 2·75 per cent. The total loss on ignition shall not exceed 4 per cent.

(b) Fineness.

The residue, by weight, on a B.S. Test Sieve No. 170 (Table 1 of B.S. 410 : 1943), when tested for fineness in accordance with the method given in Appendix B, shall not exceed

for normal Portland Cement, 10 per cent.,

for Rapid-Hardening Portland Cement, 5 per cent.

(c) Setting Time.

(i) Normal-setting Cement.—The initial setting time of normal-setting cement determined by the Vicat apparatus, in accordance with the method given in Appendix D, shall not be less than 30 minutes, and the final setting time not more than 10 hours.

(ii) Quick-setting Cement.—Where a quick-setting cement is specified, the initial setting time of the cement determined by the Vicat apparatus, in accordance with the method given in Appendix D, shall not be less than 5 minutes and the final setting time not more than 30 minutes.

(d) Soundness.

The expansion shall be determined by the " Le Chatelier " method in accordance with Appendix E and shall not exceed 5 mm. If this is exceeded, a further test shall be made after seven days' aeration, when, if the expansion does not exceed 2·5 mm. the sample shall be considered to have passed the Soundness test.

(e) Ultimate Tensile Stress.

The ultimate tensile stress shall be determined by the method given in Appendix F.

(i) Normal Cement.—The average ultimate tensile stress of four cement mortar briquettes, composed of onepart by weight of cement to three parts by weight of Standard Sand, shall not be less than :—

At 3 days after gauging 330 lb. per sq. in. (23·2 kg. per sq. cm.).

At 7 days after gauging 430 lb, per sq. in (30·2 kg. per sq. cm.).

In all cases the average ultimate tensile stress at seven days shall be greater than the average ultimate tensile stress at three days. The Standard Sand shall be a natural quartz sand, of the white variety from Leighton Buzzard, thoroughly washed and dried. It shall pass through a standard wire woven sieve, B.S. No. 18. and shall be retained on a standard wire woven sieve, B.S. No. 25.

(ii) Rapid-hardening Cement.—Where a rapid-hardening cement is specified the average ultimate tensile stress of four standard mortar briquettes shall be not less than :—

At 1 day after gauging 300 lb. per sq. in. (21·1 kg. per sq. cm.).

At 3 days after gauging 455 lb. per sq. in. (32 kg. per sq. cm.).

In all cases the average ultimate tensile stress at three days shall be greater than the average ultimate tensile stress at one day.

PACKING AND MARKING.

3. Unless otherwise agreed between the purchaser and the vendor the cement shall be delivered in paper bags containing 1·12 lb. net with the weight and the manufacturer's name or brand clearly marked thereon.

STORAGE.

4. The cement shall be stored in a suitable weather-tight building, and in such a manner as to permit access for the proper inspection and identification of each consignment.

REJECTION.

5. Any consignment of cement which does not comply with all the requirements of this specification may be rejected.

CERTIFICATES OF QUALITY, ETC.

6. The manufacturer shall, if required, furnish free of cost to the purchaser in respect of each consignment of cement sold, a certificate setting out results of tests and analyses and showing that the cement complies with the requirements of this specification. Any vendor(other than the manufacturer) shall furnish, on request, free of cost to the purchaser, a copy of such certificate with each consignment of ½ ton or more of cement sold.

The purchaser shall be free at all times to take samples of any consignment for test and to reject the consignment concerned if the results of the tests prove that the consignment does not comply with the terms of this specification. The furnishing by the vendor of the certificate as set out above shall not prejudice or over-ride the purchaser's rights in this connection.

METHODS OF SAMPLING AND TESTING.

7. The cement shall be sampled and tested in accordance with the methods of sampling and testing described in Appendix A.

APPENDIX A.

Taking of Samples.

Samples for testing may be taken by the purchaser or his representative or by the superintendent of the works for which the cement is required or his representative.

One test sample shall be taken from each 100 tons or part thereof. Each sample shall consist of approximately equal portions selected from at least five separate bags or from at least five different positions in the heap or heaps when the cement is loose. Each sample shall weigh approximately 10 lb.

The vendor shall give every facility for taking and packing, the samples and for the identification later of the cement sampled.

APPENDIX B.

Tests for Fineness.

The sieve to be used shall be prepared from wire cloth, nominal mesh No. 170, Table 1, B.S. 410 : 1943 Test Sieves. The wire cloth shall be woven (not twilled) and carefully mounted on the frames without distortion. The sieving surface shall be not less than 50 sq. in. (322-58 sq. cm.) and the depth of the sieves shall be not less than 2¾ in (69.85 mm.) measured from the surface of the wire cloth.

100 g. of cement shall be placed on the sieve and continuously sifted for a period of 15 minutes. Air-set lumps in the samples may be broken down with the fingers, but nothing shall be rubbed on the sieve.

APPENDIX C.

Determination of Normal Consistency of Cement Paste.

The Vicat apparatus shall be used with a 10 mm. diameter brass plunger, 50 mm. long, with flat lower end, and loaded so that the plunger and load together weigh 300 g. The mould to be used shall be 80 mm. diameter and 40 mm. deep.

500 g. of cement shall be gauged with a measured quantity of clean fresh water, and the time from the moment of adding the water to commencing to fill the mould shall not be less than three minutes nor more than five minutes. The mould resting upon a non-absorbent plate shall be completely filled, the operator's fingers and an ordinary gauging trowel (weighing about 200 g.) only being used. The surface of the paste shall be smoothed off level with the top of the mould. The temperature of the room and of the cement and water at the time the operations are being performed shall be from 58° to 64° F. (14·4° to 17·8° C.). The mould, immediately it is filled, shall be placed, resting on its plate, under the 10 mm. diameter brass plunger ; the plunger shall be lowered gently until in contact with the surface of the trial block and then suddenly released and allowed to sink into it. The trial block apparatus shall be kept during the whole time of setting in an atmosphere of 90 per cent. humidity and free from draughts. The quantity of water used in gauging is to be regulated until the paste is such that the plunger comes to rest 5 to 7 mm. above the bottom of the trial block. The amount of water used to obtain this result shall be expressed as a percentage by weight of the dry cement, from which by reference to Table 1, the percentage of water to be used for gauging a cement paste of normal consistency may be determined, as well as the percentage of water to be used for gauging 3 to 1 Standard Sand and cement mortar.

APPENDIX D.

Tests for Setting Time.

The Vicat apparatus shall be used to determine the setting times of the cement. The needle for the initial setting test shall be 1 mm. square in section and have a flat end and shall be loaded so that the needle and load together weigh 300 g. The needle for the determination of the final setting time shall be of the same cross-section but with a metal attachment 5 mm. in diameter hollowed out to form a sharp circular edge and with the needle projecting 0·5 mm. below it. The mould shall be 80 mm. diameter and 40 mm. deep.

500 g. of cement shall be gauged with the necessary quantity of water to form a cement paste of normal consistency and the mould filled in the manner and under the conditions described in Appendix C.

Initial Setting Time.—For the determination of initial setting time the mould shall then be placed resting on its plate under the 1 mm. square needle. The needle shall then be lowered gently until it is in contact with the surface of the test block and suddenly released and allowed to sink into it, the operation being repeated until the needle just fails to reach the base of the test block. The time from the moment of adding the water to the cement until the needle just fails to pierce completely the test block shall be initial setting time.

Final Setting Time.—For the determination of final setting time, the 1 mm. square needle is removed from the rod of the Vicat apparatus and replaced by the 1 mm. square needle with the 5 mm. diameter metal attachment, which is gently lowered to the surface of the test block. The cement shall be considered to have finally set when the needle makes an impression on the surface of the test block but the circular attachment fails to mark it.

APPENDIX E.

Tests for Soundness.

The test for soundness shall be made by the " Le Chatelier " method. The standard apparatus consists of a split cylinder forming a mould 30 mm. internal diameter and 30 mm. deep. Two indicators with pointed ends are symmetrically attached to the mould, one on each side of the split. The distance from the centre of the mould to the line joining the points of the indicators is 165 mm.

The cement shall be gauged to form a paste of normal consistency as described in Appendix C. The mould shall be placed on a glass plate and filled with the paste, the edges of the mould being kept gently together during the operation. The mould shall be then covered with another glass plate and a small lead weight placed on top, and the whole immersed in water at a temperature of from 58° to 64° F. (14·4° to 17·8° C.) for 24 hours.

The distance between the indicator points shall then be measured and the mould again immersed in water, within the temperatures mentioned above. The water shall then be brought to boiling point in from 25 to 30 minutes and kept boiling for 3 hours. The mould shall then be removed from the water and allowed to cool and the distance between the indicator points again measured. The difference between the two measurements gives the expansion of the cement. Should the expansion exceed 5 mm. a further test shall be made from the same sample after it shall have been aerated for 7 days, by being spread out to a depth of 70 mm. in a room at standard temperature. The expansion determined as described above shall not now exceed 2·5 mm.

APPENDIX F.

Strength Test.

The briquettes shall be of the shape and dimensions shown in Fig. 1, and shall be prepared in the following manner :—

Cement and sand in the proportion of one part by weight of cement to three parts by weight of the Standard Sand shall be gauged withclean fresh water the percentage of water to be used being determined from Table I. The mortar gauged as above shall be filled into the moulds whose internal dimensions are of the sizes and shape necessary to form briquettes of the dimensions shown in Fig. 1. Each mould shall be placed on a non-absorbent or metal plate. After filling the mould, more mortar is placed on the top and beaten down with a standard spatula until the mortar is level with the top of the mould. The mould shall then be turned over and the operation repeated on the other side, the mortar being beaten down until water appears on the surface. The flat only of the spatula shall be used, and no other method or apparatus shall be used for ramming the mortar in this operation. The briquettes shall be finished off in the moulds by smoothing the surface with the blade of a trowel.

The standard spatula shall be of steel with a wooden handle attached, and shall have a total length of approximately 355 mm. The flat shall be about 73 mm. long, 46 mm. wide, 5·6 mm. thick at the centre, tapering to the edges. Its weight shall not exceed 350 g. and its centre of gravity shall be practically in the centre of the length of the spatula.

The briquettes shall be kept in a damp box or chamber with a relative humidity of 90 per cent. for 24 hours after gauging, when they shall be taken out of the moulds and immediately immersed in clean water and kept there until required for testing. After the briquettes are taken out of the water and until they are tested, they must be kept wet.

The briquettes shall be tested for ultimate tensile stress at the periods after filling the moulds mentioned in Clause 2 (e). The ultimate tensile stress shall be the average ultimate tensile stress of the four briquettes for each period. The briquettes shall be held centrally in metal jaws of the shape shown in Fig. 2, and thin oiled paper or other suitable material shall be placed between the surfaces of the briquette and the jaws so as to distribute the load as uniformly as possible. The load shall be uniformly applied commencing at zero and increasing at the rate of 100 lb. per sq. in. in 12 seconds.

TABLE I.—PERCENTAGES OF WATER FOR GAUGING CEMENT PASTE AND 3 TO 1 STANDARD SAND AND CEMENT MORTAR.

TABLE 1.—PERCENTAGES OF WATER FOR GAUGING CEMENT PASTE AND 3 TO 1 STANDARD SAND AND CEMENT MORTAR.

(continued).

Na foláir tius coimhréireach de 1 orl, a bheith sna brícíní tríd id trid.

Fig. 1. —Dimensions of Briquette.

Fig. 2. —Elevation and Plan of Jaws for Holding Briquette.

GIVEN under my Official Seal, this 4th day of November, 1949.

DANIEL MORRISSEY,

Minister for Industry and Commerce.