B-1 AGREEMENT System Generated e-Tender No ... - e-Tendering

79 Dy. Executive Engineer
i) Surface defects which require rectification when forms are removed usually consist of
bulges due to movement of forms, ridges at form joints, honeycombed areas, damage
resulting from the stripping of forms and bolt hole. Bulges and ridges shall be
removed by careful chipping or tooling and the surface is then rubbed with a grinding
stone. Honey combed and other areas shall be chipped out, the edges being cut as
straight as possible and perpendicular to the surface, or preferably slightly under cut
to provide a key at the edge, of the patch. Bolt holes shall be closed by cement
mortar to ensure thorough filling.
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Shallow patches shall be treated with a coat of thin grout composed of one part of
cement and one part of sand and then filled with mortar similar to that used in
concrete. The mortar is placed in layers not more than 10 mm thick and each layer
shall be given a scratch finish to secure bond with the succeeding layer. The last
layer shall be finished to match the surrounding concrete by floating, rubbing or
tooling on formed surfaces by pressing the form material against the patch while the
mortar is still plastic.
Large and deep patches requires filling up with concrete held in place by forms. Such
patches shall be reinforced and carefully dowelled to the hardened concrete.
The same amount of care to cure the material in the patches shall be taken for the
whole structure. Curing shall be started, as soon as possible after the patch is
finished to prevent early drying. Damp Hessian cloth may be used. But in some
locations it may be difficult to hold it in place, a membrane curing compound in these
cases will be most convenient.
9. CONSTRUCTIONS JOINTS : Construction joints shall be provided and treated following the
provisions of Specification and as directed by the Engineer-in-charge.
10. DURABILITY :- Minimum cement contents for different exposures and sulphate attack are
given in Tables 4 and 5 o I.S. 456, 2000 shall be followed for design mix.
11. TESTS AND STANDARD OF ACCEPTANCE :-
11.1 Tests and Standard of acceptance criteria of design mix concrete and nominal mix concrete
shall be as follows:
Sampling and testing of Concrete shall be done as per provision of section B.6.12 of Standard
Specifications. Acceptance criteria for strength of concrete shall be as per IS 456-2000.
Case falling outside the above limit shall be examined by the Engineer on Merits in each
case.
11.2 DEFECTIVE CONCRETE : Any concrete which gives substandard results, or is severely
damaged due to cracking or shows excessive honey combing and exposure of reinforcement,
if exhibits any fault which in the opinion of the Engineer, seriously impairs its function, may be
declared as defective concrete. Such non acceptable concrete shall be removed from the site
and replaced by fresh concrete of the specified quality by the contractor at his own expenses.
Alternatively in case of acceptable concrete, the Contractor shall carry out whatever other
remedy the Engineer may reasonably suggest "Small rendering shall be done by the
Contractor without extra cost."
12 KEEPING RECORDS : The record of mix design, mixing, slum, testing of C.C. cubes etc.
shall be maintained in accordance with Section B-6.13 of the Standard Specification.
Signature of Contractor No. Of Corrections Executive Engineer