Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 06: Concrete and Steel Works  1 of 18  Code for buildings to be built in disaster areas, 2007, Ministry of Public Works and Settlement  Code for infrastructure to be built in disaster areas, 2007, Ministry of Public Works and Settlement  The Contractor shall provide printed or digital copies of these standards at the site office, for the use of  the Engineer's and Contractor's personnel.  The Contractor shall keep accurate and up to date records of concreting, showing for each day when  sections of the works were concreted. These records shall include:  The laboratory where the concrete tests have to be carried out shall be approved by the Engineer and  the Employer and be accessible for the said parties at any time. The laboratory should preferably be  placed at the site.  The grades of Concrete to be used in the works are shown in the following table:  6_Vol3_d4.3_Section 6 Concrete and steel works_en_GIR_rev6.docx  Concrete  class  Minimum cement  con- tent  Characteristic  cylinder  strength at 28 days  Characteristic cube strength at 28 days  Works to be used  C30/37  300 kg/m$^{3}$  30 N/mm$^{2}$  37 N/mm$^{2}$  -  Water retaining structures  -  Water channels  -  Manholes  and  Valve  chambers  -  Silos  -  Precast concrete elements  -  Buildings  C20/25  250 kg/m$^{3}$  20 N/mm$^{2}$  25 N/mm$^{2}$  - Thrust blocks  -  Pipe casings  -  Roads & kerbs  -  Surface drainage units  C16/20  200 kg/m$^{3}$  16 N/mm$^{2}$  20 N/mm$^{2}$  -  Fill concrete and mass  concrete  inside/under  water  retaining structures  -  Cable channels and  cable manholes (if cast in situ)  C 8/10  150 kg/m$^{3}$  8 N/mm$^{2}$  10 N/mm$^{2}$  -  Blinding  layer  below  structures  6.1.3 Record of concreting  6.1.4 Classes of concrete   Class of concrete, volume of concrete placed and number of batches used for each location.   Number of batches produced, weight and kind of cement used, volume of concrete placed,  number of batches wasted or rejected   Results of all concrete tests, including identification of which part of works the sampled mate- rial is representative   Date, time, weather conditions and temperature 