GAIL (India) Limited

252. In case the concrete has hardened a bit more than (a), but can still be easily removed by a lighthand pick, the surface shall be raked thoroughly and the loose concrete removed completelywithout disturbing the rest of the concrete in depth. Then a rich mortar layer of 12 mmthickness, shall be placed on one cold joint and then the fresh concrete shall be placed on themortar layer and vibrated thoroughly penetrating deep into the layer of concrete.3. In case the concrete at the joint has become so stiff that it cannot be remoulded and mortar orslurry does not rise in spite of extensive vibration, a tongue and groove joint shall be made byremoving some of the older concrete and the joint shall be left to harden at least for 12-24hours. It will then be treated as regular construction joint and the surface preparation of thesame, before placement of concrete, shall be as described in the appropriate clauses of thesespecifications.3.25 Sub-standard concreteShould the work strength of controlled concrete fall below the specified strength, Engineer shalldecide:1. To reject the work, in which case the Contractor shall replace the defective work with concreteof required strength and bear all costs for dismantling and replacing including cost ofassociated form work, reinforcement, embedded parts & all associated works.2. To accept the work at a reduced rate, in which case the unit rate payable for sub-standard workwill be reduced by GAIL (INDIA) LTD., directly in proportion to the work strength ascompared to the specified strength. The Engineer may, in addition, require other testsperformed on the respective structural member so accepted period to its acceptance with orwithout necessary corrective measures and in each such case, the Contractor shall bear allcosts for all such tests or corrective measures, besides the reduction in the unit rates asspecified herein.3. Concrete of strength below fifteen (15) percent of the specified strength will not be accepted.4. The test load shall be 125% of the maximum superimposed load for which the structure wasdesigned. Such test load shall not be applied before 56 days after the effective hardening ofconcrete. During the test, struts strong enough to take the whole load shall be placed inposition leaving a gap under the members. The test load shall be maintained for 24 hoursbefore removal.5. If, within 24 hours of the removal of the load, the structure does not show a recovery of atleast 75% of the maximum deflection shown during the 24 hours under load, the test loadingshall be repeated after a lapse of alteast 72 hours. The structure shall be considered to havefailed to pass the test if the recovery after the second test is not at least 75% of the maximumdeflection shown during the second test.If the structure is certified as failed by the Engineer, the cost of the load test shall be borne by theContractor.3.26 Optional TestsThe Engineer, if he so desires, may order tests to be carried out on cement, sand, coarse aggregate,water in accordance with the relevant Indian Standards.Tests on cement shall include1. Fineness test2. Test for normal consistency3. Test for setting time4. Test for soundness5. Test for tensile strength6. Test for compressive strength7. test for heat of hydration (by experiment and by calculation) in accordance with IS:269.Tests on sand shall include1. Sieve test.