3. Concrete Works

Mixes and aggregates

a) The choice of cements for making concrete mixes shall be made in accordance with therequirements of:

• SNiP 3.03. 01 -87 "Bearing and guarding structures";

• GOST 23464-79 "Concretes. Classification”

b) Acceptance of cements shall be performed according to GOST 22236-85 "Cements.

Acceptance rules".

c) Transportation and storage of cements shall be performed according to GOST 22237-85"Cements. Packing, labelling, transportation and storage".

d) Concrete mix composition, preparation, acceptance rules, control and transportation methodsshall comply with GOST 7473-85 "Concrete mixes. Technical conditions".

e) Concrete aggregates shall be factional and washed. Applying of natural mixture of sand andgravel without size grading is not allowed.

Casing

а) The Contractor shall use timbering types in accordance with GOST R 52085-2003 "Timbering. Terms and Definitions".

b) Installation and acceptance of timbering, dismantling of cast-in-situ structures, cleaning and lubrication of timbering shall be made as per the project of performance of works.

c) The following measures shall be provided during installation of timbering:

• required durability, rigidity and invariability under the influence of technological loads, andlow adhesion to concrete;

• given accuracy of sizes of structures erected inside timbering and correctness of structureslocation in space;

• possibility of rapid assembly and disassembly without damaging the concrete structure beingbuilt;

• unhampered installation of reinforcement, embedded items, laying and compaction ofconcrete mix;

• required density in interfaces between individual elements, excluding laitance leakage andformation of build-ups;

• availability of compensators that reduce thermal stresses in timbering during concreteheating;

• possibility of timbering heat insulation or installation of heating elements inside timberingduring concrete works in winter conditions.

d) During acceptance of installed timbering, supporting structures and fastenings, it is necessary tocheck:

• bearing timbering and its supporting structures;

• correct arrangement of timbering supporting structures, as well as rigidity and invariability ofthe entire timbering in general;

• correctness of timbering installation, caps, embedded items.

Reinforcement and embedded items

а) During installation of reinforcement and embedded structures, it is necessary to:

• perform checking of timbering and eliminate detected defects;

• perform assembly of reinforcement and embedded items in sequence, which ensures their correct (designed) position;

• provide required gap for formation of protective concrete layer between reinforcement and timbering, by fastening of the corresponding fixtures on reinforcement;

• fix the assembled reinforcement and embedded items to prevent their shifting during concrete casting.

Anchor bolts

Pins for anchor bolts, nuts and washers shall be m ade of the steel grades, the mechanicalproperties of which are not worse than steel grade St3 as per DSTU 2651:2005 (GOST 380-2005) "Carbon steel of ordinary quality. Grades".

Concrete casting of structures

а) Prior to packing of concrete, all structures and their elements, to be covered during subsequent performance of works (reinforcement, embedded items) shall be accepted with issuing the examination report on covered-up works.

b) Concrete shall be laid in the concrete casting structures by horizontal layers of equal thickness without gaps, with consistent direction of laying in the same direction in all layers.

c) During compaction of concrete, it is not allowed to rest vibrators on reinforcement and embedded items.

d) Protective layer of concrete for the main reinforcement shall provide joint operation of reinforcement with concrete at all stages of structure operation, as well as protection of there inforcement from external environment and temperature effects.