a thickness of approximately one inch. Alternatively the entire curbing may be constructed of concrete with white portland cement. Washed mortar sand shall meet all the requirements for mortar sand and shall be of a light color satisfactory to the Engineer. The reflecting surface mortar shall be placed immediately after placing of the base concrete. In no case shall more than twenty minutes elapse between the placing of the base concrete and the placing of the reflecting surface. Scoring or surface deformation and finish of the reflecting surface shall conform to the details shown on the plans. 609.07 Bituminous Concrete Curbing. (a) Excavation.-Excavation shall conform to the requirements of subsection 609.03(a). (b) Preparation of bed.-When curbing is constructed on a portland cement concrete base, bituminous pavement or bituminous treated base, the bed shall be thoroughly swept and cleaned by compressed air. The surface shall be thoroughly dried and, immediately prior to placing of the bituminous mixture, shall receive a tack coat of bituminous materials of the type and grade specified in the contract. The rate of application of the tack coat material shall be between 0.05 to 0.15 gallons per square yard of surface. The Contractor shall prevent the spread of tack coat to areas outside of the area to be occupied by the curb. (c) Placing.-Bituminous curbing shall be constructed by use of a self-propelled automatic curber or curb machine or a paver with curbing attachments. The automatic curber or machine shall meet the following requirements and shall be approved prior to its use. (1) The weight of the machine shall be such that compaction is obtained without the machine riding above the bed on which curbing is constructed. (2) The machine shall form curbing that is uniform in texture, shape and density. (3) The Engineer may permit the construction of curbing by means other than the automatic curber or machine, when short sections or sections with short radii are required, or for such other reasons as may be warranted. The resulting curbing shall conform in all respects to the curbing produced by the use of the machine. Weather limitations for construction of bituminous curbs shall be the same as covered under subsection 401.11. The bituminous mixture shall be placed at a workable temperature of not less than 225°F. The curbs shall be placed to an accurate alignment and shall have a high density free of honey-combs. When joining to a section of curb that has become cold, the contact surface of the cold curb shall be given a thin uniform tack coat of bituminous material prior to placing the fresh bituminous mixture against the cold joint. The curbs shall be protected from traffic by barricades or other suitable method until the curb has hardened. (d) Painting and sealing.—When sealing or painting is required, it shall be performed only on a curbing which is clean and dry and which has reached an ambient temperature. (e) Backfilling.-Backfilling shall conform to the requirements of subsection 609.04(g). 609.08 Resetting Curb. (a) Salvage of curbing.-The Contractor shall carefully remove, store and clean any curbing specified for resetting. The Contractor shall replace any existing curbing that is to be reset, which is lost, damaged or destroyed as a result of his operations, or because of his failure to store and protect it in a manner that would eliminate its loss or damage. (b) Excavation.-Excavation and bedding shall conform to the requirements of subsection 609.03(a). (c) Resetting curb.-The curb shall be set on a firm bed with the front top arris line conforming to the required line and grade. All sections of curbing shall be set so that the maximum opening between adjacent sections is not more than 34-inch wide for the entire exposed top and face. Any dressing of the ends of the curbing necessary to meet this requirement shall be done by the Contractor. After the curb has been set, the joints shall be completely filled with mortar as specified. (d) Backfilling.-The spaces in front and back of the curb shall be refilled to the required elevation with suitable material. This material shall be thoroughly tamped in layers of not over 6 inches in depth. (e) Cutting and fitting.—Cutting or fitting shall be done as necessary to install the curbing at the locations directed. Method of Measurement 609.09 Curbing, both new and reset, will be measured by the linear foot along the front face of the section at the finished grade elevation. Combination curb and gutter will be measured along the face of the curb. No deduction in length will be made for drainage structures installed in the curbing section or for driveway openings where the gutter is carried across the drive. Bed course material will be measured by the ton or by the cubic yard. Basis of Payment 609.10 The accepted quantities of curbing, including excavation, dowels, expansion material, reinforcing steel and bedding will be paid for at the contract unit price per linear foot for each kind and type of curbing specified and per ton or cubic yard for bed course material complete in place. Such payment shall include all subgrade preparation. The work of furnishing, placing and tamping selected earth backfill material behind curbs will not be paid for directly, but will be considered as a subsidiary obligation of the Contractor. Payment will be made under: Pay item 609(1) Portland cement concrete curb,-inch depth, type 609(2) Portland cement concrete gutter-depth, type 609(3) Portland cement concrete curb and gutter,-inch depth, type 609(4) Bituminous concrete curb,-inch depth 609(5) Stone curb,-inch depth. 609(6) Reset curb .... 609(7) Bed course material. Pay unit Linear foot. Linear foot. Linear foot. Linear foot. Linear foot. Linear foot. Cubic yard. 609(8) Bed course material If no pay item for Bed Course Material appears in the bid schedule, payment for any bed course material shown on the plans will be considered to be included in the bid price for bid item shown. Reinforcement, excavation, backfill, disposal of surplus materials, expansion joint material and other related miscellaneous items will not be paid for separately but payment therefor will be included in the bid price of the curb, gutter, or curb and gutter. Section 610.-STONE MASONRY STRUCTURES Description 610.01 Scope. This work shall consist of the construction of stone masonry structures and the stone masonry portions of composite structures, in accordance with these specifications and in reasonably close conformity with the lines, grades, dimensions, and design shown on the plans or directed by the Engineer. 610.02 Classes of Masonry. The class of masonry required for each part of a structure will be that indicated on the plans and described herein. Cement Rubble Masonry shall consist of roughly dressed stones of various sizes and shapes laid in random courses in cement mortar, as specified in this section. Class A and Class B Masonry shall consist of stones shaped, dressed, and laid brokencoursed in cement mortar in accordance with the requirements specified in this section for the designated class. Dimensioned Masonry shall consist of broken-coursed ashlar masonry composed of stones having two or more dimensions shown on the plans and in accordance with the requirements of this section. Materials 610.03 Stone. The stone shall be sound and durable, quarried by approved methods, and will be subject to the Engineer's approval. It shall preferably be native to the vicinity of the work and shall be of a kind that previous use has proven to be satisfactory for the specified purpose. (Vicinity of the work shall be understood to mean within a radius of approximately 50 miles). The stone shall be properly protected at all times. In addition to the above requirements, stone for dimensioned masonry shall be free of reeds, rifts, seams, laminations, and minerals which, by weathering, would cause discoloration or deterioration. (a) Sizes and shapes.-Each stone shall be free from depressions and projections that might weaken it or prevent it from being properly bedded, and shall be of such shape as will meet both architecturally and structurally the requirements for the class of masonry specified. When dimensions for stones are shown on the plans, the stones shall be of the size shown. When no dimensions are shown on the plans, the stones shall be furnished in the sizes and face areas necessary to produce the general characteristics and appearance as indicated on the plans. In general, stones shall have thicknesses of not less than 5 inches, widths of not less than 11⁄2 times their respective thicknesses, with minimum width of 12 inches, and lengths of not less than 12 times their respective widths. Where headers are required their lengths shall be not less than the width of bed of the widest adjacent stretcher plus 12 inches. At least 50 percent of the total volume of the masonry shall be of stone having a volume of at least 1 cubic foot each. (b) Dressing.-The stone shall be dressed to remove any thin or weak portions. Face stones shall be dressed to provide bed and joint lines with a maximum variation from true line as follows: (c) Bed surfaces.-Bed surfaces of face stones shall be normal to the faces of the stones for about 3 inches and from this point may depart from normal not to exceed 1 inch in 12 inches for dimensioned masonry and 2 inches in 12 inches for all other classes. (d) Joint surfaces.— In all classes of masonry except dimensioned masonry, the joint surfaces of face stones shall form an angle with the bed surfaces of not less than 45 degrees. In dimensioned masonry, the joint surfaces shall be normal to the bed surfaces. They shall also be normal to the exposed faces of the stone for at least 2 inches from which point they may depart from normal not to exceed 1 inch in 12 inches. The corners at the meeting of the bed and joint lines shall not be rounded in excess of the following radii: (e) Arch ring stone joint surfaces.-Arch ring stone joint surfaces shall be radial and at right angles to the front faces of the stones. They shall be dressed for a distance of at least 3 inches from the front faces and the soffits, from which points they may depart from a plane normal to the face not to exceed 3/4 inch to 12 inches. The back surface in contact with the concrete of the arch barrel shall be parallel to the front face and shall be dressed for a distance of 6 inches from the intrados. The top shall be cut perpendicular to the front face and shall be dressed for a distance of at least 3 inches from the front. When concrete is to be placed after the masonry has been constructed, adjacent ring stones shall vary at least 6 inches in depth. (f) Stratification.-Stratification in arch ring stones shall be parallel to the radial joints and in other stones shall be parallel to the beds. (g) Finish for exposed faces.-Face stones shall be pitched to the line along all beds and joints. The kind of finish for exposed faces shall be as shown on the plans or the special provisions. The following symbols will be used and they shall be understood to represent the type of surface or dressing specified below: Fine pointed (F. P.).—In which the point depressions shall be approximately 8 inch apart with surface variation not to exceed 8 inch from the pitch line. Medium pointed (M. P.).—In which the point depressions shall be approximately 5% inch apart with surface variations not to exceed 4 inch from the pitch line. Coarse pointed (C. P.).—In which the point depressions shall be approximately 1 to 11⁄4 inches apart with surface variations not to exceed 3⁄4 inch from the pitch line. Split or seam face (S.).—In which the surface shall present a smooth appearance, be free from tool marks, with no depressions below the pitch line and no projection exceeding 3⁄4 inch beyond the pitch line. Rock faced (R. F.).—In which the face shall be an irregular projecting surface without indications of tool marks, with no concave surfaces below the pitch line, and with projections beyond the pitch line, when measured in inches, not exceeding the figure preceding the symbol as used on the plans or in the special provisions, e.g., "11⁄2 R. F." means projections beyond the pitch line not exceeding 11⁄2 inches. Where a "variable rock face" is specified, stones of the same height of projection shall be well distributed. Removal of drill and quarry marks from the faces of stones in cement rubble masonry will not be required. 610.04 Quarry Operations. Quarry operations and delivery of stone to the point of use shall be organized so as to insure keeping deliveries well ahead of masonry operations. A sufficiently large stock of stone of the kinds being used in the work shall be kept on the site at all times, to permit adequate selection of stone by the masons. 610.05 Mortar. Mortar shall conform to the requirements of subsection 705.05. Construction Requirements 610.06 General. All construction other than stone masonry shall conform to the requirements prescribed in other sections for the several items of work entering into the completed structure. 610.07 Excavation and Backfill. Excavation and backfill shall conform to the requirements of Section 206 modified as follows: For filled spandrel arches the filling shall be carefully placed in such manner as to load the ring uniformly and symmetrically. The filling material shall be acceptable to the engineer and shall be placed in horizontal layers, carefully tamped, and brought up simultaneously from both haunches. Wedge-shaped sections of filling material against spandrels, wings, or abutments will not be permitted. 610.08 Falsework. Arch centering shall be constructed in accordance with construction drawings submitted by the Contractor as required by subsection 105.02. Suitable wedges shall be provided for raising or lowering the forms to exact elevation and for taking up any settlement occurring during loading. Centering shall be lowered gradually and symmetrically so as to avoid overstresses in the arch. When directed, centering shall rest upon approved jacks in order to take up and correct any slight settlement which may occur after the placing of masonry has begun. In general, centering shall be struck and the arch made self-supporting before the railing or coping is placed. For filled spandrel arches such portions of the spandrel walls shall be left for construction subsequent to the striking of centers as may be necessary to avoid jamming of the expansion joints. When additional falsework and bracing are necessary to hold the stones in proper position, the Contractor shall construct such falsework and bracing in a manner satisfactory to the Engineer, but failure of the Engineer to order their construction will not release the Contractor from his obligation to build a satisfactory structure. 610.09 Sample Section. If required by the special provisions, the Contractor shall build, at a site designated by the Engineer, an L-shaped sample section of wall not less than 5 feet high and 8 feet long, showing examples of face wall, top wall, method of turning corners, and method of forming joints. No masonry other than the foundation masonry shall be laid prior to the approval of such samples. 610.10 Arch Ring Templet. If required by the special provisions, a full-size template of the arch ring shall be laid out near the quarry site, showing face dimensions of each ring stone and thickness of joints. The template shall be approved by the Engineer before the shaping of any ring stone is started, and no ring stone shall be placed in the structure until all ring stones have been shaped, dressed, and approved by the Engineer. 610.11 Selection and Placing. When the masonry is to be placed on a prepared foundation bed, the bed shall be firm and normal to, or in steps normal to, the face of the wall, and shall have been approved by the Engineer before any stone is placed. When it is to be placed on foundation masonry, the bearing surface of this masonry shall be cleaned thoroughly and wetted immediately before the mortar bed is spread. All masonry shall be constructed by experienced workmen. Face stones shall be set in random bond so as to produce the effect shown on the plans and to correspond with the sample section approved by the Engineer. Care shall be taken to prevent the bunching of small stones or stones of the same size. When weathered or colored stones, or stones of varying texture, are being used, care shall be exercised to distribute the various kinds of stones uniformly throughout the exposed faces of the work. Large stones shall be used for the bottom courses and large, selected stones shall be used in the corners. In general, the stones shall decrease in size from the bottom to the top of work. All stones shall be cleaned thoroughly and wetted immediately before being set, and the bed which is to receive them shall be clean and moistened before the mortar is spread. They shall be laid with their longest faces horizontal in full beds of mortar, and the joints shall be flushed with mortar. The exposed faces of individual stones shall be parallel to the faces of the walls in which the stones are set. The stones shall be so handled as not to jar or displace the stones already set. Suitable equipment shall be provided for setting stones larger than those that can be handled by two men. The rolling or turning of stones on the walls will not be permitted. If a stone is loosened after the mortar has taken initial set, it shall be removed, the mortar cleaned off, and the stone relaid with fresh mortar. Arch ring stone shall be carefully set to exact position and held in place with hardwood wedges until the joints are packed with mortar. 610.12 Beds and Joints. The thickness of beds and joints for face stones shall be as follows: |