concrete of the desired strength, or if such screening and remixing will produce concrete of the desired strength with enough less cement so that the saving in the cost of cement win exceed the cost of screening and remixing.

10. Consistency. No more water shall be used than is necessary to produce a concrete which can be worked thoroughly into the forms and around the reinforcing. The consistency shall be measured by the slump test in the method described in the 1921 report of the Committee on Masonry, American Railway Engineering Association. The maximum slump shall not exceed 6 inches. The consistency shall be checked up from time to time.

11. Mixing. Mixing shall be done in a batch mixer of approved type, equipped with a suitable charging hopper, water storage, and water measuring device. The entire contents of the drum shall be discharged before recharging. Each batch shall be mixed for not less than 1% minutes after all the materials are in the mixer, during which time the mixer shall rotate at a peripheral speed of about 200 feet per minute. The volume of the mixed batch shall not exceed the manufacturer's rated capacity. The retempering of concrete which has partially hardened shall not be permitted. In cold weather aggregate shall be heated, if necessary, to remove frost and frozen lumps.

(III) DEPOSITING CONCRETE

12. General. Before depositing concrete the molds shall be thoroughly cleaned and coated with non-staining mineral oil or other approved material. The mixer should be so located that the concrete can be discharged directly into the molds or conveyed to the molds in such a manner as to cause no separation of the ingredients. Each mold shall be completely filled in one continuous operation.

13. Molds. Molds shall be substantial, rigid, and true to plan. Metal molds are more satisfactory than wooden molds.

14. Placing Reinforcing. The reinforcing shall be securely and continuously held in its proper position in the post during the placing of the concrete and until the post is removed from the mold. Metal spacers that would cause distinct lines of cleavage in the post shall not be used. The reinforcing shall be supported as often as is necessary to prevent its sagging to any appreciable extent due to its own weight or to the weight of the wet concrete.

15. Compacting. Concrete shall be thoroughly compacted into the molds and around the reinforcing. This is best accomplished by giving the molds a jogging or vibratory motion during and after depositing.

16. Finish. All posts shall have a clean, smooth finish. If any pockets or holes are discovered upon removal from the molds, they shall be immediately filled with a mixture of one part cement to two parts fine aggregate. Pockets or holes more than 1⁄2 inch in depth or more than 1⁄2-inch in diameter, or any exposure of the reinforcing shall cause the rejection of the post.

(IV) CURING AND HANDLING POSTS

17. Curing. The posts shall remain in the molds until the concrete has thoroughly hardened and in no event for less than 24 hours after placing. During this time and until they are cured the posts shall be carefully handled and protected from shock. When the posts are removed they shall be stocked in a nearby vertical position and protected from direct sunlight. They shall be kept wet by sprinkling for eight or ten days after being made. They should be cured for not less than 90 days, when cured naturally, before being shipped or set. Posts shall not be cured out of doors during freezing weather.

(V) MISCELLANEOUS

18. Inspection. All materials and all processes of manufacture shall be subject to inspection and approval at all times. Free access shall be provided for all authorized inspectors to all parts of the plant in which the posts or the materials are made, stored or prepared.

19. Tests. All testing of materials used in the manufacture of posts, all preparing, storing and testing of concrete specimens, as provided in Section 8 hereof, and all screen analyses of aggregates, shall be made in accordance with the methods adopted or approved by the American Railway Engineering Association and in effect at the time such tests, analyses, etc., are carried out. In case the American Railway Engineering Association shall not have approved or adopted any methods for such tests, analyses, etc., the same shall be made in accordance with the methods then adopted or approved by the American Society for Testing Materials.

20. Patents. The manufacturer or contractor shall pay all royalties for the use of patented designs or devices or forms of construction and protect the Railway Company from all claims of infringements or liability for the use of such patents.