- Max allowable temp for all types of concrete is 32 0 c.
- Max allowable fall of pouring 1st 1.2 mts.
- Max allowable slump 100+- 25 mm, water adding should not be allowed.
- Max allowable time is 2hrs after batching
- Normally ‘opc’ used for structural & src used for sub structures.
- Normally types of mix a.40/20, b.30/20, c.25/20, d 20/20.: where ’40’ is compressive strength & 20 is the site of agg.
B. Wet mix
- Minimum cbr should be 80 @ 100 % compaction.
C. Road base
- Normally moisture content should be in between 4.5% to 6.5%.
- Normal grading 70% agg (size = 5mm down) & 30% sand.
- Agg used in wet mix : crushed & in road base natural.
- Minimum compaction required is 98%
D. Prime coat
- Average rate of application should be 0.8 to 1.2 kgs/sqm.
- Temperature should be in between 600 c to 900 c curing time 48hrs.
- Cut back asphalt mc =medium curing rc=rapid curing = sc=slow curing.
E. Tack coat
- Average rate of application should be 0.15 to 0.35 kgs/sqm.
- Temperature should be in between 100 c to 600 c.
- Tack coat should be sprayed min 2hrs before laying aspahlt
- Inter locking paving blocks:6cm thick for footpath:8cm for parking.
- Typical cross section shows:15cm=sub base,5cm coarse sand,6cm=tiles.
- First compaction after paving tiles,final after sand spreading..
H. Kerb stone
- Types upstand kerb,drop kerb,heel kerb,flush kerb(dimension varies)
- Fixing g.l.compacted 7cm con blind.fixed by mortar ,15cm con haunching.
- Pointing gap should be 4mm expansion joint should be at very 10mc.
- All the services should be below 90cm from the frl(finish road level)
- Less than 90cm below frl,should be protected concrete production.
- Normal use :future or spare ductsplit duct,proposed duct
- Normally pvc & upvc pipes used for ducts,dla from 100mm to as required.
- Pipe lines :water =30cm to 60cm a/c irrigation =28cm pvc storm water=225mm .
- Mentral test & pressure tests conducted to confirm clear & lekage
- Test pressure shall be 1, 5 times the max working pressure & bar .
- Ducts above speci level shall be bedded & surrounded with 150mm con 15//20 .
- During backfill warning tape shall be installed over buried pipes.
- All ducts shall be provided std color drancord & std duct markers.
- Trench backfill shall be with appr mat & in 15cm compacted layers.
J. Safety measures:
- Trenches more than 1m deep shall protected with sheet piles (shoring) .
- Construction site should secured with cones, barrier & waring tapes.
- Temporary diversion sign boards, flash lights, should be installed.
K. Test a/c
- Marshal test (for stablity, flow, stifness, vim, vfb, vma) & core test (comp).
- Test for agg grading in asphalt also to find out bitumen content.(e/w)
- Mdd againest omc (proctor test) cbr field density (com) tests
- Slump (workablity) test, test for compressive strength (by cubes).
- Paving blocks & kerb stones shall be tested for crushing value.
- Is a mixture of coarse aggregate, fine aggregate filler material & bitumen binder.
- Mix types /dense mix &stiff mix grad a.40/50 & b,60/70.
- Normal asphaltic layer thickness/b.c=80mm bi.c=60mm w.c =40mm.
- Normal aggregate/ Base Course =37mm & down binder .c=25mm & down wearing c =19mm & down.
- Required min compaction /b.c=97: bi c=97: w.c=98%.
- If compaction is more than 101.8% the asphalt should be rejected
Allowable temp in asphalt
- surface temp before laying =18 0 min
- batching temp=1630c max
- laying temp=1350 c to 1630 min & max
- breakdown temp=1200 to 1400 c
- temp in joints should be 900 c min.
- In logitudinal joints 15cm over lap should be maintained.
- All logitudinal & transverse joints should cut vertical.
- Asphalt laying & rolling should be done from lower to upper.
- Asphalt should be laid max 1.50 m to get req tem in joints.
- Modified asphalt to increase stiffness 10 to 15% of chemcrete is mixed with bitumen while batching also to increase stability.
- Bleeding surface flow of bitumen (occurs due to over spray of tack coat) by placing hot mix over sprayed should be removed.
- Segregation / accumulation of agg. should replaced with fine mix
- To know no of passes required for of min comp, trail area 30mt to be prepared.
- Inspector to check during asphalt, segregation open texture tearing action using straight edge constantly, & tem regularly.
- Pot holes: less asphalt thin asphalt surface, poor drainage & ponding due to oil & diesel patches slippage cracks with form.
- Cracks can be repaired by, bitu- sealant, hot mix asphalt emulsion slurry.
- Camber = two side slope (nor1.5%) cross fall=one side slope(nor2%)
- In long & tran joints between layers 15cm offset is kept for good comp.
- While asphalt paving the speed of paver should be 4 to 6 km/min.
- Weight of STR (Steel Tandom Roller) should be in between 8 to 12 ton.
- Weight of PTR (Pneumatic Tyre Roller) should be 20 to 25 ton/ tyre pressure should be in between 6 to 6.3 kg/sqcm or 80 to 110 psi/
- Rollers speed should 5km/hr, should maintain overlap in passes/
- Staggered rolling should be done in passes, to avoid channeling/
- First & final rolling should be with STR & in middle with PTR.
- First to seal temp, final for smooth finish, PTR for inform comp.
- Veg oil lubrication used on PTR tyre ,should not be excess.
- While rolling at super elevation drive wheel should be forwarded, to avoid pushing of material.
- After 24 hrs re rolling is avoided design period will be reduced.
- Traffic should not be allowed min 7 days on fresh asphalt pavement.
- Transverse joints should be in min 50cm offsets for each line.
- FRL(finish road level) should be 15cm below the kerb stone
- Normal widths c.w=6m 7.3m & 11.5m p.p =2.5m d.p =5.5m s.w.=2.5m:mn=3m.
- Prime coat is sprayed over wet mix to seal the moisture content.
- Asphalt should layer 25% more to get req thickness after compaction.
- String line supported 10m interval pegs to get uniform levels.
- Joints should cut verticaly(900) toget proper compaction in joints.
- Asphalt leveling at joints should done careful to avoid jump & sag.
- Embankment should be in 15cm compacted layers approved material.
- CBR of exist mat should be 15.at formation level.
- Formation level should be compacted 95% and CBR should be 15%.
- Improved sub grade should be compacted 95% and CBR should be 30.
- Use of saline water. Should be avoided in Construction & compaction works.
- Before executing job trial trench's or pits to be excavated to find existing service.
- Construction area shall be checked with cable detector to locate the exist cables.
- Reference point for all levels shall be taken from standard bench mark.
- For trench where water table is high dewatering pump shall be used.
- Before laying pipe lines, 15cm sand bedding should be layed.
- Curing shall be done for min 7 days for all concrete work.
- For emergencies curing compound is allowed to proceed for further job.
- 25 mm grouting shall be done for base of storm water manhole.
- GRP liner shall be provided for all sewer manholes.
- Rock fill layer is used in road const, where the water table is high.
- Earth work= grader, showel, back hoe, static roller & vibrator roller.
- Asphalt works= Paver, STR (Steel Tandom Roller) PTR (Pnuematic Tyre Roller).
- Others: transit mixer, spray tanker, bob cat, dumber, baby roller.
- Equipment used in asphalt should be without leakage of oil & diesel.
- All const works shall execute under: std spec limits & tolerances.