32. Water.—Water used for concrete shall be fresh, and reasonably clean.
33. Care and Handling of Concrete Material.—Cement must not be allowed to become wet or damp. It shall be stored until used, whether in storehouses or on the street, so that no part of the packages shall be nearer than four (4) inches to the ground or pavement, and shall be effectually covered so that rain cannot reach it. Sand and stone, if stored on the street, shall be on lumber floors.[[9]] The stone shall be thoroughly wetted a sufficient time before being placed in the concrete to allow any surplus water to drain away, but shall remain moist where it reaches the concrete platform or mixer.
34. Ratio of Concrete Materials.—Concrete will be composed of one part Portland cement, ... parts of sand and ... parts of broken stone, and the proper quantity of water, all measured by volume.[[10]] The unit of measurement shall be the barrel of cement which shall be considered as containing four (4) cubic feet. The materials shall each be measured in such manner and with such accuracy that the quantities used will not vary more than seven (7) per cent. from the quantities required in the ratio named above for each batch of concrete.
35. Mixing Concrete.—If mixed by hand, concrete shall be mixed on platforms of iron or wood of sufficient size to admit of proper manipulation of the concrete. The sand shall be first spread evenly over the platform and the cement evenly distributed over the sand. These two materials shall then be mixed dry until a uniform and homogeneous mixture is secured. Sufficient water shall then be added and the mixing resumed and continued until a mortar of uniform consistency and texture is produced and distributed in an even layer over the platform. The stone shall then be distributed over the mortar and mixed therewith until the mortar is evenly distributed through the mass and every fragment of stone is well coated with mortar, sufficient additional water being added as the mixing progresses to produce a rather wet, but not sloppy, concrete.[[11]] Machine mixing of concrete will be preferred, provided the machine used secures equal accuracy in the ratios of materials and equally as good mixing as prescribed above for hand-mixing. Machine-mixed concrete must be delivered from the machine upon a wood or metal platform, or directly into barrows.
36. Placing the Concrete.—Concrete shall be placed on the sub-grade in such a manner as to prevent as far as possible the separation of the mortar from the stone. It shall be evenly distributed in a single horizontal layer of such depth that, after ramming, it will be not less than ... inches thick. Immediately after being so placed it shall be well rammed until a compact mass is produced with its upper surface parallel to and ... inches below the pavement datum. Depressions that may appear during the ramming may be filled with concrete of the same composition as used for the foundation, except that smaller-sized stone shall be used; mortar alone must not be used for this purpose, nor shall the upper surface of the concrete be plastered with mortar. The surface of the concrete shall not be broomed or troweled.[[12]]
37. Setting of Concrete.—After the concrete is completed it shall remain undisturbed until it be firmly set. The time allowed for setting shall not be less than five days, and as much longer as, in the judgment of the Engineer, may be necessary, depending upon the temperature of the weather and the setting qualities of the cement. During this period no hauling or traveling over the concrete must be permitted unless its surface be first protected by a covering of plank. The Contractor shall, if necessary, keep the concrete moist by wetting it, with hose, or otherwise, until twenty-four (24) hours before it is to be covered with the pavement surface.
38. Measurement of Concrete.—Concrete will be measured and computed in cubic yards as found completed on the street, the thickness being taken as ... inches. The contract price for concrete foundation covers the cost of providing all the materials required, making, placing and ramming the concrete, and keeping it moist for the necessary period.
FOUNDATION OF OLD PAVING STONE
39. Foundations made of old stone paving blocks shall be constructed as follows:
Upon the sub-grade prepared as specified in Section 26, shall be spread a layer of good sand to an even depth of one and one-half (1½) inches. The paving blocks, whether taken up from the street to be paved, or brought from other streets or storage yards, shall be cleaned of all adhering earth, dirt and street refuse. The blocks shall then be set on the bed of sand, on edge, perpendicular to the grade, with their long dimension at right angles to the line of the street, in courses composed of stones of the same width, extending entirely across and at right angles to the axis of the street. Stones in adjoining courses shall break joint at least two inches. Joints between courses or stones, or along the curbstones, shall not exceed one inch in width. The stone shall be fitted closely around manholes or other structures in the street. The stones shall be so set in the bed of sand that after being rammed as hereafter specified, their tops shall be at the proper grade. After being thus set in place the stone shall be rammed with paving rammers having wooden faces and weighing not less than thirty (30) pounds, so as to force each stone to a good bearing in the sand below, and to bring its top to a uniform grade, parallel to and ... inches below the pavement datum. No stone shall project more than one-fourth (¼) inch above the proper grade, and stones whose tops, after ramming, are more than one-half (½) inch below such grade, shall be raised, additional sand placed under them, and reset and re-rammed to the proper grade and bearing. After the ramming shall have been completed, the joints between the stones shall be filled with mortar. The mortar shall be composed of Portland cement and sand, complying with the specifications for these materials in Sections 29 and 30. One part of cement and three parts of sand, by volume, shall be thoroughly mixed dry, and then made into mortar with sufficient quantity of water to produce a mortar of such consistency that it will just flow freely into the joints between the stones. All the joints between the stones must be completely filled with this mortar before it has begun to set. The mortar filling shall be brought even with, but not above, the tops of the stones. After the filling is thus completed, the foundation must stand undisturbed until the mortar shall have set firmly, in no case less than five days. The mortar must be kept moist during the period allowed for setting.[[13]]