S.I. No. 354/1949:

STANDARD SPECIFICATION (COARSE AND FINE AGGREGATES FROM NATURAL SOURCES FOR CONCRETE) ORDER, 1949.

STANDARD SPECIFICATION (COARSE AND FINE AGGREGATES FROM NATURAL SOURCES FOR CONCRETE) 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 (Coarse and Fine Aggregates from Natural Sources for Concrete) 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 5 : 1949.

SCHEDULE.

PART I.

COARSE AND FINE AGGREGATES FROM NATURAL SOURCES FOR CONCRETE.

PART II.

SPECIFICATION.

SCOPE.

1. This specification applies to the naturally occurring materials, crushed or uncrushed, used in the production of concrete for normal structural purposes, including roads.

DEFINITIONS.

2. For the purpose of this specification the following definitions shall apply :

(a) Test Sieve of any particular size or number shall mean the British Standard test sieve of that size or number as prescribed by the British Standards Institution in its publication of serial number 410 of the year 1943.

(b) Fine aggregate shall mean aggregate mainly passing a ³/16 in test sieve and containing only so much coarser material as is permitted in this specification.

(c) Coarse aggregate shall mean aggregate mainly retained on a ³/16 in. test sieve and containing only so much finer material as is permitted for the various types described in this specification.

(d) All-in aggregate shall mean aggregate containing a proportion of material of all sizes as obtained from the pit, river bed, foreshore, quarry or crushing plant.

(e) Percentages except where otherwise stated shall mean percentages by weight.

QUALITY OF AGGREGATE.

3. Aggregates shall consist of naturally occurring sand, gravel or stone, crushed or uncrushed, or a combination thereof. They shall be hard, strong, durable, clean and free from adherent coatings and shall not contain excessive quantities of flat or elongated particles.

(a) Harmful Impurities.

Aggregates shall not contain harmful material in sufficient quantity to affect adversely the strength or durability of the concrete or, in the case of reinforced concrete, to attack the reinforcement. Mica, shale or similar laminated materials or soft particles shall not be present in such a form or in such quantity as to affect adversely the concrete.

When tested in accordance with the method given in Appendix C the quantity of harmful impurities passing a No. 200 test sieve shall not exceed (1) in the case of fine aggregate 3 per cent. for natural sand and 5 per cent. for crushed stone and (2) in the case of coarse aggregate 1 per cent.

Fine aggregate when tested for organic impurities in accordance with the method given in Appendix D shall not show a depth of colour exceeding that of the reference solution given in Appendix D.

(b) Crushing.

The extent of crushing of aggregate, when determined according to the method given in Appendix E shall not exceed 30 per cent. for concrete wearing surfaces (roads, paving, etc.) and 45 per cent. for other concrete.

(c) Frost Resistance.

Coarse aggregate for concrete liable to be exposed to the action of frost shall not be of a type that is liable to suffer from the action of frost.

GRADING.

4. (a) Coarse Aggregate.

The grading of a coarse aggregate when analysed as described in Appendix B shall be within the limits given in Table 1 for each nominal size.

TABLE 1.--GRADED COARSE AGGREGATES.

(b) Single-sized Coarse Aggregates.

Where coarse aggregate graded in accordance with Table I is to be obtained by combining single-sized aggregates, the grading of the single-sized aggregates, when analysed as described in Appendix B, shall be within the limits given in Table 2 for each nominal size.

TABLE 2.--SINGLE-SIZED COARSE AGGREGATES.

(c) Fine Aggregates.

(i) The grading of a fine aggregate, when analysed as described in Appendix B, shall be within the limits given in Table 3.

TABLE 3.--FINE AGGREGATES.

(ii) When the fine aggregate is to be used in concrete containing more than 480 lb. of cement per cubic yard of concrete, the limit passing the No. 52 test sieve may be lowered from 10 per cent. to 5 per cent.

(iii) When the fine aggregate is to be used in concrete containing less than 350 lb. of cement per cubic yard of concrete, the limit passing the No. 52 test sieve may be raised from 30 per cent. to 33 per cent.

(iv) Fine aggregate containing less than 10 per cent. of material passing the No. 52 test sieve may be used provided an approved satisfactory inorganic material is added to correct the deficiency in grading.

(v) A fine aggregate intended for use in medium and lean concrete shall contain not less than 2 per cent. of material passing the No. 100 test sieve.

(vi) In order to control the grading of fine aggregate from any one source a preliminary sample shall be submitted before actual deliveries are made. This sample shall be representative of the material which it is proposed to supply. The fineness modulus of this sample and of samples from subsequent consignments shall be determined in the manner described in Appendix B. If the sample from any consignment shows a variation in fineness modulus greater than plus or minus 0-2 from the fineness modulus of the preliminary sample, the consignment shall be rejected or at the option of the purchaser it may be accepted subject to such changes in the proportion of materials as he or his representative may deem necessary by changes in grading of the fine aggregate.

In order to determine the fineness modulus of a fine aggregate the accumulative percentage by weight retained on each of the test sieves Nos. 100, 52, 25, 14, 7, ³/16 in., ³/8 in. shall be calculated from the sieve analysis, in accordance with the method given in Appendix B. The percentages shall be added together, and the fineness modulus shall be found by dividing this sum by 100.

(vii) When fine aggregate consisting of crushed stone sand is to be used in the manufacture of cast concrete products, the limit of material passing the No. 100 test sieve may be raised to 15 per cent.

(d) All-in Aggregates.

The proportion of the coarse aggregate part to the fine aggregate part in a single all-in aggregate shall be as specified by the purchaser.

A single all-in aggregate, when separated on a ³/16 in. test sieve and the separate parts tested in accordance with the method given in Appendix B, shall conform to the following conditions : (1) the coarse aggregate part shall be within the limits given in Table 1, and (2) the fine aggregate part shall be within the limits given in Table 3.

A mixture of two all-in aggregates, one mainly coarse and the other mainly fine, when separated on a ³/16 in. test sieve and the separate parts tested in accordance with the method given in Appendix B, shall conform to the like conditions.

SAMPLING.

5. The method of sampling and the amount of material to be provided for the purpose shall be in accordance with the provisions of Appendix A.

SUPPLIER'S CERTIFICATE AND COST OF TESTS.

6. The supplier shall satisfy himself that the material supplied conforms to the requirements of this Specification, and, if requested, shall furnish a certificate to this effect to the purchaser or his representative.

If the purchaser or his representative requires independent tests on the material supplied, the samples for the tests shall be taken before delivery or immediately after delivery at the option of the purchaser or his representative.

The supplier shall supply free of charge the material required for the tests.

The cost of the tests shall be borne as follows

(a) by the supplier in the event of the results of the test showing that the material does not comply with the specification,

(b) by the purchaser in the event of the results of the test showing that the material complies with the specification

INFORMATION TO BE FURNISHED BY THE SUPPLIER.

7. When required by the purchaser or his representative, the supplier shall furnish the following information about the source of supply of the material :

(i) County.

(ii) Townland.

(iii) Name of Quarry or Pit.

(iv) In the case of material dredged from seas, estuaries or rivers, the precise locality from which the material was taken.

Appendix A.

METHOD OF SAMPLING.

A main sample of not less than ½ cu. yard (or 12 cwt.) shall be obtained as follows :--

(i) In the case of sampling from stock piles, twelve initial samples of about 1 cwt. each shall be taken from different parts of the stock pile, care being taken to avoid sampling a segregated area of coarse or fine material. These initial samples shall be well mixed together.

(ii) In the case of sampling from bins, six initial samples of about 1 cwt. each shall be taken from the top surface of the bin and a single initial sample of about 6 cwt. from the discharging chute. These initial samples shall be well mixed together.

(iii) When sampling during loading or unloading of a vehicle or boat, twelve initial samples of about 1 cwt. each shall be taken at approximately equal intervals throughout the loading or unloading operation. These initial samples shall be well mixed together.

The main sample shall be quartered down to the amount of sample required for the laboratory. The size of sample required for the laboratory shall be 1 cwt. for fine aggregate, 2 cwt, for coarse and all-in aggregate up to 1 ½ in. nominal size and 3 cwt. for aggregate of 2 in. nominal size.

Material of each nominal size shall be separately sampled and dispatched to the testing laboratory, care being taken to avoid the loss of any fine material.

The sample to be used in any test required by the specification shall be obtained by quartering from the laboratory sample.

Appendix B.

SIEVE ANALYSIS.

The weight of the sample for sieving shall be not less than that set out in Table 4 for the nominal size of aggregate.

TABLE 4.--WEIGHT OF SAMPLE FOR SIEVE ANALYSIS

The sample shall be dried, and weighed. It shall then be passed successively through the test sieves specified in Tables 1, 2, or 3 for the aggregate respectively starting with the largest test sieve.

If sieving is carried out by hand, each sieve shall be shaken separately over a clean tray for a period of not less than two minutes. The shaking shall be done with a varied motion--backwards and forwards, left to right, circular clockwise and anti-clockwise--and with frequent jarring so that the material is kept moving over the sieve surface in frequently changing directions. Material smaller than ³/₈ in. shall not be helped through the sieve by hand or by brushing. Lumps of fine material, if present, may be broken by gentle pressure with the fingers against the side of the sieve.

If sieving is carried out with a nest of sieves on a machine, the sieving shall be continued for not less than 10 minutes with each nest.

On completion of sieving, the material retained on each sieve, together with any material cleaned from the mesh, shall be weighed on a balance sensitive to 0-1 per cent. of the weight of the test sample.

Appendix C.

DETERMINATION OF AMOUNT OF MATERIAL PASSING A NO. 200 TEST SIEVE.

The laboratory sample shall be thoroughly mixed and shall contain sufficient moisture to prevent segregation. A representative sample, sufficient to yield not less than the appropriate weight of dried material, as shown in Table 5 shall be selected from the laboratory sample.

TABLE 5.--SIZE OF SAMPLE.

The sample shall be dried to constant weight at a temperature between 100° C. and 110° C. and weighed (Weight A). The material shall be deemed to be of constant weight when the difference in successive weighings at the temperature specified at intervals of four hours does not exceed 0·01 per cent. of the weight of the material.

The sample shall then be placed in a pan or container and covered with water. The pan or container shall be large enough to permit of vigorous agitation without accidental loss of any part of the sample or of water. The contents of the container shall be agitated vigorously so that the fine material is brought into suspension and the wash water shall then be poured immediately over a No. 14 test sieve and a No. 200 test sieve arranged with the coarser sieve on top. Care shall be taken to avoid decantation of the coarse particles of the sample. The operation shall be repeated until the wash water is clear. All material retained on the sieves shall be returned to the washed sample.

The washed material shall be dried to constant weight at a temperature between 100° C. and 110° C. and weighed (Weight B). The results shall be calculated from the following formula :

Percentage of material passing a No. 200 test sieve =

When check determinations are desired, the wash water shall be either evaporated to dryness or filtered through tared filter paper which subsequently shall be dried and the residue weighed (Weight C) The percentage shall be calculated from the following formula :

Percentage of material passing a No. 200 test sieve =

Appendix D.

DETERMINATION OF ORGANIC IMPURITIES.

The aggregate to be tested shall be used as delivered without drying. A representative sample weighing 1 lb. shall be selected from the laboratory sample. A 12 oz. clear-glass bottle graduated to 12 oz. shall be filled to the 4 ½ oz. mark with the sample. A 3 per cent. solution of sodium hydroxide in water shall be added until the volume of the sand and liquid indicated, after shaking, is 7 fluid ounces. The bottle shall be stoppered, shaken vigorously and then allowed to stand for 24 hours.

The amount of organic impurity shall be assessed by the extent to which the liquid above the sand is darker in colour than the reference solution.

The reference solution shall be prepared by adding 2·5 ml. of a 2 per cent. solution of tannic acid in 10 per cent. alcohol to 97.5 ml. of a 3 per cent. sodium hydroxide solution. The solution shall then be placed in a 12 oz. bottle, stoppered, shaken vigorously and allowed to stand for 23 hours. It shall then be shaken and allowed to stand for a further 1 hour before comparison with the solution above the sand.

APPENDIX E.

DETERMINATION OF EXTENT OF CRUSHING.

The following apparatus is required for the test :

(a) Three sizes of open-ended mild steel cylinder, with plunger and base plate. The size of cylinder to be used shall depend on the nominal size of aggregate and shall be as given in Table 6. The cylinder with plunger and base plate shall be constructed as indicated in Fig. 1 and shall be of the dimensions given in Table 7.

(b) Straight metal tamping rods of circular cross-section round-nosed at one end and of the appropriate dimensions given in Table 7.

(c) A scale or balance accurate to ±5 g. in the case of samples to be tested in the 12 in. cylinder, ±1 g. for the 6 in. cylinder and ±0.2 g. for the 3 in. cylinder.

The size of material to be tested shall be the predominant size of stone present as determined by sieving between the consecutive sieves given in Table 8. The test sample shall be obtained from the laboratory sample by thoroughly sieving on the appropriate test sieves given in Column 1 of the table so that the whole of the material to be tested passes the larger sieve and is retained on the smaller sieve. The sample shall be dried for 24 hours in a well-ventilated oven at a temperature of 100° C. to 110° C. and cooled in a desiccator. The approximate quantity of material required for two tests is given in Table 8.

The whole of the material to be tested shall be weighed on the appropriate scale or balance (Weight A).

The cylinder of the test apparatus shall be put into position on the base plate. The material to be tested shall be inserted in the cylinder to a depth of approximately one-third of the final depth as given in Column 4, Table 8, and subjected to 25 strokes from the tamping rod. The remaining two-thirds shall be added and tamped in the same way. The final depth of the aggregate as given in Table 8 is such that when the plunger is placed in position on top of the aggregate, the top edge of the flange on the plunger exactly coincides with the top edge of the cylinder, as shown in Fig. 1. The material remaining after the test sample has been added to the cylinder shall be weighed (Weight B). The weight of the test sample is A--B.

The apparatus, with the test sample and plunger in position, shall then be placed in a compression testing machine and the appropriate load given in Table 8 shall be applied at a uniform rate, so that the maximum load is reached in 10 minutes. The load shall be released, the apparatus removed from the testing machine and the whole of the material removed from the cylinder and sieved on the appropriate test sieves given in the Table. The fraction passing the sieve shall be weighed (Weight C).

The weight of fines formed in the test (Weight C) shall be expressed as a percentage of the total sample weight thus :

and shall be regarded as the extent of crushing for the purposes of Clause 3 (b) of this specification.

TABLE 6--SIZE OF CYLINDER.

TABLE 7--DIMENSIONS OF CYLINDERS.

*The 3 in. and 6 in. plungers may, if convenient, be made from solid mild steel, in which case only the outside dimensions will apply.

Fig. 1.--Aggregate crushing test--dimensions of cylinder, base plate and plunge.

GIVEN under my Official Seal this 23rd day of December, 1949.

DANIEL MORRISSEY,

Minister for Industry and Commerce.