1 of 18  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 06: Concrete and Steel Works  Faces in contact with concrete shall be free from adhering grout, projecting nails, splits or other de- fects. Joints shall be sufficiently tight to prevent the leakage of cement grout and to avoid the for- mation of fins or other blemishes. Faulty joints shall be caulked. 20 mm by 20 mm chamfers shall be  formed on the external corners of concrete members, unless otherwise specified. Internal corners shall  similarly be provided with 20 mm fillets.  Formworks for exposed surfaces shall be laid out in a regular and uniform pattern with the long di- mension of panels vertical and all joints aligned.  If openings of the formwork for the escape of water used for washing out are made, they shall be  formed so that they can be conveniently closed before placing the concrete.  Connections shall be constructed to permit easy removal of the formwork and shall be strong enough  to retain the correct shape during consolidation of the concrete.  Metal ties or anchors within the form shall be so constructed as to permit their removal to a depth of at  least 50 mm from the face without injury to the concrete. All fittings for metal ties shall be of such  design that, upon their removal, the cavities which are left shall be of the smallest possible size.  Spreader cones or ties shall not exceed 25 mm diameter. The cavities shall be filled with cement mor- tar and the surface left sound, smooth, even and uniform in color.  Formwork shall be true to line and braced and strutted to prevent deformation under the weight and  pressure of the unset concrete, constructional loads, wind, and other forces. Beams spanning more than  3 m shall have an upward camber of 1.5 mm per m of span.  Concrete shall normally not be placed in lifts deeper than 3 m. For lifts higher than 3 m, openings for  placing the concrete shall be provided in order to avoid segregation of the concrete.  The approved mould oil or other material shall be applied to faces of formwork to prevent adherence  of the concrete. Such coatings shall be insoluble in water, non-staining and non-injurious to the con- crete. Liquids that retard the setting of concrete shall be used only when approved. Mould oil, retard- ing liquid and similar coatings shall be kept from contact with the reinforcement or previously cast  concrete.  Before any concrete is placed, forms shall be properly cleaned by washing out with water and/or air  under pressure to remove sawdust, shavings, metal and other foreign matter. All water shall then be  drained and mopped out from the formwork. In no case shall concrete be placed in the forms until  such forms have been approved by the Engineer. Such approval shall not relieve the Contractor of his  responsibility for the formwork.  Details of any fixtures to be cast into the concrete shall be to the approval of the Engineer. No fixtures  shall be attached to the concrete by shot-firing without prior permission of the Engineer. Notwith- standing any such authorization, the Contractor shall take full responsibility for any damage caused to  the structure and make good to the satisfaction of the Engineer.  Mixing, placing and curing of concrete shall be made in accordance with TS 1247 and TS 1248.  6.1.10 Placing and compaction of concrete  6_Vol3_d4.3_Section 6 Concrete and steel works_en_GIR_rev6.docx 