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precasted concrete block (IS 15658)
- 1. Precast concrete blocks (IS15658) Jai prakash Neeraj
- 2. Spcification • Paver block Aspectratio < 4 • Aggregate So3 < .5% Water absorption < 2% Nominal maximum size = 12 mm • Pigment Pigment quantity <9% by weight of cement concrete Particles Should be finer than cement • Durability Dimension and tolerance :- Table 2 thickness and wearing layer :- Table 2 Compressive strength for individual paver block > 85% of specified strength (table 3)
- 3. Grade designation ofpaver blocks Zero slump concrete used. Design according to different traffic load as per table1. Quality of paver block depends on w/c,vibration,cement grade,aggregate quality,curing etc .
- 4. Precaution Pigment shall not containzinc compound . Lead pigment shall not be used . Check visual defects carefully . The compressive strength of two layer block should meet the specified requirement .
- 5. Requirements Compressive strength requirementof paver block as per table 3 For water absorption ,the mean value of 3 sample shall not be more than 6% by mass of samples. Sample requirement is given in table 4.
- 6. Tests for concreteblock Aspect ratio Water absorption Compressive strength Abration resistance Tensile splitting strength Flexural strength Freezing thaw durability
- 7. Aspect ratio Aspect ratio= mean length/mean depth
- 8. Water absorption W(%) =(ww-wd)/wd Ww = wet of block removed after 24 hours immerging in water Wd = wet of specimen after drying it in ventilised oven at 107 degree for 24 hours
- 9. Compressive strength C.S. =maximum load / plan area C.S. = apperent compressive strength of individual block. Corrected compressive strength is calculated by multiplying c.s. to correction factor given in table
- 10. Abration resistance •test isdone on abration testing machine. It can be done on dry as well as wet surface. •calculate the density of wearing surface (PR). •Disc speed should be 30rpm. •dv is measure of abration resistance .
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