Compressive Strength Pounds per Square Inch 1:3 Mortar 2 Sand 4 Pebbles 3441.0 TABLE 2 TESTS OF LUMNITE CEMENT CONCRETE BY E. L. CONWELL & Co. Compression Tests of 6"x12" Cylinders Each value represents strength in compression of 3 specimens in pounds per square inch. Age of Specimen 1 Day 3 Sand 6 Pebbles 2071.0 Chapter XI BITUMINOUS PAVEMENTS SPECIFICATIONS COMMITTEE-1925 E. A. KINGSLEY, Chairman. F. P. SMITH.......... FELIX KLEEBERG. JOHN B. HITTELL. PREVOST HUBBARD. .Dallas, Texas .New York City New York City .Chicago, Ill. New oYrk City COMMITTEE REPORT The Committee on Bituminous Pavements has no new specifications to present to the society this year. Some consideration was given to the formulation of a specification for an asphaltic concrete pavement of the fine graded aggregate type, such as is known as stone filled sheet asphalt. It was thought best, however, to defer the preparation of this specification for another year in order to utilize to best advantage the results of important researches on asphalt paving mixtures now being made by a number of investigators. At the Boston convention last year, a specification for asphalt Macadam pavement was presented, but was not referred to letter ballot because at the meeting an important amendment was offered, which had not had the Committee's prior consideration and approval. This amendment has since been approved and published in the 1924 Proceedings. No criticism of the amendment has been received, but at a meeting held this week a slight addition was incorporated in amended paragraph 8(c) for the purpose of insuring greater uniformity in distribution of asphalt. The proposed addition is in connection with the sentence on page 373, of the 1924 Proceedings, reading as follows: "In order to prevent lapping at the end junctions of two applications, the distributor shall be promptly shut off when the application begins to thin just before the tank is empty. The Committee recommends that this sentence be changed to read as follows: "In order to prevent lapping at the end junctions of two applications, the distributor shall be promptly shut off, and if necessary to prevent dripping, a drip pan shall be inserted under the nozzles, when the application begins to thin just before the tank is empty. The Committee further recommends that this specification as amended be accepted by the society and referred to letter ballot for adoption. Upon the request of a number of producers of rock asphalt it is suggested that the 1925-1926 Committee on Bituminus Pavements consider the preparation of specifications for one or more types of rock asphalt pavements, where these types have been proven satisfactory under present traffic conditions for paving purposes. The Committee also suggests that the new Committee prepare specifications for a stone filled sheet asphalt pavement. Spreading and compacting aggregate. First application of asphalt cement. Filling surface voids with intermediate aggregate. Condition of finished pavement.. 2345 1780 9 10 11 1. General Description. The asphalt macadam pavement shall consist of coarse broken stone or slag consolidated by rolling while in place on the road bed, the interstices between. the coarse particles being subsequently filled with hot asphalt cement and finer particles of crushed stone or slag. It shall be laid to a finished thickness of three (3) inches upon a founda tion constructed in accordance with the specifications for Foundation and shall be finished with a seal coat of hot asphalt cement and stone or slag chips or fine gravel. All materials and methods of construction shall conform to the requirements of these specifications. Materials 2. Sources of Supply. (a) Approval of sources of supply of mineral aggregate shall be obtained from the engineer prior to the delivery of materials and samples of each shall be submitted as directed by the engineer. (b) A one-pound sample of the asphalt cement that the contractor proposes to use must be submitted to the engineer before the use of such material in the work will be permitted. Every refined asphalt and asphalt cement admitted under these specification shall be equal in quality to the recognized standard for its particular kind or type of asphalt. (c) Unless otherwise permitted by the engineer, all samples shall be submitted at least three weeks prior to use of the materials in the performance of the work and in no case shall they be used until they have been examined and approved by him. Whenever during the course of the work, new deliveries of paving materials are received by the contractor, samples of these shall at once be submitted to the engineer and their use in the work will not be permitted until they have been examined and approved by him. 3. Methods of Testing. Unless otherwise specified, all tests shall be conducted in accordance with the latest Standards or Tentative Standards of the American Society for Testing Materials. 4. Mineral Aggregate. (a) The mineral aggregate shall consist of broken stone, mine tailings or slag. It shall be of reasonably uniform quality thruout and shall be clean and free from dust and an excess of flat or elongated pieces. Rock or mine tailings from which it is produced shall have a per cent of wear or not more than six (6). Slag from which it is produced shall have a per cent of wear of not more than ten (10) and shall weigh not less than seventy (70) pounds per cubic foot for each size specified. (b) When tested by means of laboratory screens the coarse, intermediate and fine aggregates shall meet respectively the fol Note: The test values for quality of stone incorporated in this specification are suggested as the lowest safe requirements where heavy traffic must be provided for. It is not expected, however, that the limits for size and quality will be applicable to all localities and conditions. 5. Asphalt Cement. The asphalt cement shall be homogeneous, free from water and shall not foam when heated to 175°C. (347°F.). It shall meet the following requirements for physical and chemical properties: I. Flash Point (open cup) not less than....175°C. (347°F.) III. Ductility at 25°C. (77°F.), not less than..... .30 cm. IV. Loss at 163°C. (325°F.), 5 hours, not more than..3 per cent V. Proportion of bitumen soluable in carbon .50 per cent Note: Where less than 99 per cent of the asphalt cement is soluble in carbon tetrachloride, the percentage of bitumen (solubility in carbon disulphide) shall be reported. Construction 6. General Conditions. The base or foundation must be dry and free from loose or foreign materials when the coarse aggregate is spread upon it and not more than sufficient stone for an average day's work shall be spread in advance of rolling and filling. 7. Spreading and Compacting Coarse Aggregate. (a) The coarse aggregate shall be spread upon the base in a uniformly |