placing, finishing, curing and jointing concrete pavement finishing curing... · placing,...
TRANSCRIPT
Placing, finishing, curing
and jointing concrete
pavement
ASCP Forum 14 March 2016 Todd Myers Director/Owner TSM Civil Project Management
President ASCP
TOPICS
1. Placing
2. Finishing
3. Curing
4. Jointing
PLACING, FINISHING, CURING &
JOINTING CONCRETE PAVEMENTS
ASCP Forum 14 March 2016
1. PLACING – Mixing & Hauling
ASCP Forum 14 March 2016
Local premix concrete supplier (Dry mix)
Delivery in agitators
1. PLACING – Fixed Form
ASCP Forum 14 March 2016
Fixed form paving
placing options
1. PLACING – Slip form
ASCP Forum 14 March 2016
Concrete Dumped on Grade
1. PLACING – Slip form
ASCP Forum 14 March 2016
Restricted Access – Material Transfer Placer
1. PLACING – Slip form
ASCP Forum 14 March 2016
Dowels/cages – Placer Spreader
1. PLACING – Where to Place?
ASCP Forum 14 March 2016
Minimise the auger/plow work. It is a paver, not a dozer
As close as possible
to its final location
For both:- slipform
- fixed-form
to minimise handling
1. PLACING – Start of day - Caution
ASCP Forum 14 March 2016
Start Day ‘Transition Pour’ Length TBA
Direction of paving
1. PLACING – End of day - Caution
ASCP Forum 14 March 2016
Need to cut back
into good concrete
Hand vibration of
‘Transition Lot’ in timely
manner at Start & End of
day
ASCP Forum 14 March 2016
2. FINISHING
Finishing: Is the process where surface marks or small localised high spots are
corrected.
This is separate activity to compaction.
ASCP Forum 14 March 2016
2. FINISHING
Helicopter floats
not suited to
pavements
They do not give
the right type of
surface texture
AND Curing
should have
started long ago.
ASCP Forum 14 March 2016
2. FINISHING – Tools & equipment
Bull float
Hand floats Wood & Steel
Scraping Straight Edge
Edging tools are not normally used at joints or edges for highway pavements
But these may be applicable for footpaths/cycle ways!
ASCP Forum 14 March 2016
2. FINISHING – Tools & equipment
Bull float
Short, light flat
blade, hinged for even contact
‘Float’ only
limited to closing surface marks only
2. FINISHING – Tools & equipment
Hand Float
Use limited to minor
‘touch up’ only near
edges
basic rules :
1. Do not hand float if
not necessary
2. Use to the absolute
minimum required
If excessive required
need fix paving process
2. FINISHING – Tools & equipment
Scraping Straight Edge
Length & weight allow
‘scrapping and filling of
pop marks or slight high
spots
About 2m (+) long
Steel angle or hollow
section, long handle
Caution - In hands of
inexperienced may
create issues
ASCP Forum 14 March 2016
2. FINISHING – Bleeding
Use either a bull
float or hand float in
a way that works
the surface bleed
water back into the
surface!!
ASCP Forum 14 March 2016
ASCP Forum 14 March 2016
3. Finishing - Texturing
Texturing is process of producing a skid
resistance surface - Micro texture
RMS R83 Up to 80 km/h
Hessian drag (or broom)
(min 38% sand in aggregate)
Over 80 km/h (and Roundabouts)
Hessian drag (longitudinal)
+ Tyning (transverse or longitudinal)
ASCP Forum 14 March 2016
3. Finishing - Texturing
Produced by;
• Hessian Drag
• Broom finish
ASCP Forum 14 March 2016
3. Finishing – Texturing hessian
KEY points for good hessian drag texturing
Attach to work bridge or platform behind paver at right angles to paving
Double layer in contact with concrete
Minimum 0.5 m (could be =1.5m) in contact with concrete.
Avoid bunching at edges
Watch for buildup of wet or dry mortar (warm weather)
Dampen at start & Renew drag each paving day
ASCP Forum 14 March 2016
3. Finishing – Texturing broom
Suggested points for good broom finish
Light broom, not heavy ‘bass’ broom.
Use only dead weight of broom – don’t lean on it,
don’t ‘gouge’ surface
Straight slightly overlapping runs at right angles to
pavement
Clean broom after each pass – knock dags out,
barrow with water and shake mortar out
ASCP Forum 14 March 2016
3. Finishing – Tyning Hand Pours
Finished product
The tynes are long to allow
‘flat curved’ contact with
concrete
ASCP Forum 14 March 2016
4. CURING
What is curing?
CURING is a process of retaining moisture at a
reasonable temperature to keep the reaction between
cement and moisture going. In the first day or so if either; • Concrete completely dries out, or
• Concrete freezes The reaction stops but CANNOT be restarted !!!
ASCP Forum 14 March 2016
4. CURING
Curing is important for;
Strength – pavement life &
Durability - surface wear resistance
ASCP Forum 14 March 2016
4. CURING
Curing – Ideal conditions
Concrete laboratory.
This is perfect,
under water &
controlled
temperature
Not practical in field
ASCP Forum 14 March 2016
4. CURING
Two main RMS requirements for
curing membrane
a continuous unbroken film (no gaps or holes when
applied)
maintained intact for 7 days (any damage made good ) or
concrete 25 Mpa
ASCP Forum 14 March 2016
4. CURING
Effectiveness of curing compounds
Wax or
hydrocarbon OK
Acrylics -
check test
certificates
carefully !
ASCP Forum 14 March 2016
4. JOINTING
“People Breathe - Concrete Cracks”**
All we can do is control where it cracks
**Dr Manton Hall UNSW (Concrete Technology 101 – 1986)
ASCP Forum 14 March 2016
4. JOINTING
Typ Joints
Along – 4.2m
Across – 4.3m
Essentially
square slabs
ASCP Forum 14 March 2016
4. JOINTING
Typically sawing 4- 8 hours after pour, depend on; • Air temp. • Conc. Temp • Wind • Season • Sun/Shade • Etc, Etc
ASCP Forum 14 March 2016
4. JOINTING
Typical Saw cut width 6-7mm Crack will form 1-5 days Cleaning is very important No sealing > 7 days Joints must be dry Common Silicone Sealants
• Dow Corning 888 • Parchem Road Seal SL
ASCP Forum 14 March 2016
PLACING, FINISHING, CURING &
JOINTING CONCRETE PAVEMENTS
Thankyou