| 1 | Providing & applying structural repairs with pre-packed dual shrinkage controlled (volume stable in wet & hardened state), single-component ready-to-use, structural grade high build, alkali-resistant, fibre-reinforced, thixotropic polymer modified repair mortar having excellent bond strength to old damaged concrete structures / surfaces in the following process:
1) Removal of loose/spalled or damaged concrete by chipping and cleaning the concrete surface to open up to 20mm behind the reinforcement steel with wire brush and with clean water 2) Cleaning the rebars with Acetone for complete rust removal and washing with water to make the surface clean. 3) Applying protective coat / bond coat using Styrene Butadiene Rubber (SBR) polymer and cement in the proportion of 1: 1 (1 part of polymer : 1 parts of cement). 4) Mixing full 25 Kg bag with clean potable water in water to product ratio of 0.12 to 0.18), mixed by heavy-duty slow speed (300 to 600 rpm) drill with spiral mixing paddle or forced action pan mixer pan for 3 minutes to achieve uniform lump free mortar consistency. 5) Applying polymer modified mortar with trowel & float. The polymer modified mortar shall have the following properties/technical parameters: (A) Properties / technical parameters of pre-packed Polymer Modified Mortar: i) Compressive strength 1 day: Min. 20 MPa (as per BS:6319 : Part 2)ii) Compressive strength 7 days: Min. 35 MPa (as per BS:6319 : Part 2) iii) Compressive strength 28 days: Min. 45 MPa (as per BS:6319 : Part 2) v) Tensile strength in 28 days: Min. 2.5 MPa (as per BS:6319 : Part 7) iv) Flexural strength in 28 days: Min. 7 Mpa (as per BS:6319 : Part 3) vi) Bond strength: Min. 5 MPa (as per ASTM : C881) vii) Water permeability: less than 1% (as per ASTM : C881) viii) Drying shrinkage in 28 days: less than 1000 microstrain (as per ASTM C 157-93) ix) Potential Alkali Reactivity : <0.1% Expansion % ( ASTM C1260) (B) Properties / technical parameters of SBR polymer bond coat material: i) Meets the requirements of BS 6319 part 2:1983 & ASTM C 190-85 standards
ii) Total solids % by mass at 105oC: 38 + 1
iii) pH value: 7.5 to 9.5
iv) Specific gravity at 27.5oC: 1 to 1.05
v) Coverage: 4.2 - 4.5 sq.m/kg per coat Notes:- (a) If ambient temperature is more than 30oC, use chilled water for mixing and store unused product in shed. Placing and finishing the same with trowel carefully compacting the same around the rebars and finishing to bring it in line with existing concrete surface on the beams, slabs, columns, etc. (b) If thickness of repair exceeds 20mm , after every 20 mm thick repair, bond coat as per process no. (3) mentioned above in the BOQ item, to be applied and further thickness of repair to be continued for each layer. (c) The surface preparation & method of application shall be as per manufacturer's technical data sheet. (d) The double tubular steel scaffolding will be paid separately in relevant item. (e) Safety Precuations:- Use wear tight-fitting, dust-resistant, chemical splash goggles and dust respirator, if airborne dust is generated, wear protective rubber hand gloves, wear appropriate clothing to prevent any possibility of skin contact. The above item of work is inclusive of all materials, SBR polymer, labour, machinery, tools & tackels, consumables, trasportation, loading & unloading, safety PPEs etc. all complete as directed by Engineer-in-charge at site using approved pre-packed polymer modified mortar suitable for structural repair works. | 250.00 | Kg |
| 2 | Providing, centering, shuttering Form work for sub-structure using PVC film faced plywood to get a neat form finish surface for all types of structures including necessary strutting, proping, staging, supports etc and deshuttering the same after the specified time all as per drawings, specifications and as directed by the Engineer-in-charge at all levels. | 60.00 | SqM |
| 3 | Providing, centering, shuttering Form work for super-structure using PVC film faced plywood to get a neat form finish surface for all types of structures including necessary strutting, proping, staging, supports etc and deshuttering the same after the specified time all as per drawings, specifications and as directed by the Engineer-in-charge at all levels. | 40.00 | SqM |
| 4 | Providing and laying in position cement concrete of 1:3:6 (1 cement, 3 crushed sand, 6 graded stone aggregate of maximum size 20 mm) with minimum cement content as per the latest revision of relevant IS codes including consolidation, finishing, curing etc. complete as per specifications and drawings but excluding the cost of Form work shuttering, centering Complete at all levels. | 5.00 | CuM |
| 5 | Providing and laying in position Reinforced Cement Concrete (RCC) of grade M-30 with minimum cement content as per the latest revision of relevant IS codes using 20mm maximum size aggregates and crushed sand of approved quality including admixtures of approved quality (plasticiser or super plasticiser) if required, including weigh batching, mechanical mixing, transporting, placing, vibrating, consolidation, finishing, curing etc. complete but excluding the cost of centering, shuttering and reinforcement complete as per specifications up to Plinth Level. | 10.00 | CuM |
