1.1. Construction preparation works:

Prepare ground plan (measure, call for motorbike, material…)

Arrange construction site
­Prepare implementing design

 Commence the building
1.2. Cast a curb, separating strip.
1.3. Building foundation, crushed rock, road space is extended, the road under separating strip is separated from right edge and old right parallel road:
Building process includes:

The enlarged foundation of road under separating strip

­Aggregate base with crushed rock

Building aggregate base with crushed rock: For 80-centimet- main roads, divide into 4 layers to build, for parallel roads and roads under separating strip, depending on the thickness of warping compensation, layers of construction are divided as long as the thickness of each layer is not over 20cm after building compaction. 

1.4. Install a curb:
+ Make the layer of concrete bedded by stone 1x2 M150.
+ Fix the form, create the curb

+ spray prime coat with the standard of 1kg/m2

+ Make the layer of medium-grainedhot asphalt concrete 10cm thick

+ check compaction of medium-grainedhot asphalt concrete layer after 2 days
1.6. Build compensating macadam, put separating strip and pave medium-grainedhot asphalt concrete on real road:
As for part having over 12cm-thick warping compensation

Warping compensation: the practical road surface is ploughed up 12cm deep on average, and then compensation is by crushed rock type 1

Set up the separating strip

Make concrete layer + bed of rock 1x2 M150
 Put in the separating strip+
­ Mix medium-grainedhot asphalt concrete layer:
 Blow out dust, sprinkle tack coat 1kg/m2+
medium-grainedhot asphalt concrete layer is +10cm thick
 As for part having the thickness of warping compensation v<12cm.
­ Warping compensation:
 Blow+ clean road surface, sprinkle tack coat 0.5kg/m2

Make medium-grainedhot asphalt concrete layer with the average compensation+ warp 7cm

Set up the separating strip:
 Build bedding concrete layer + rock 1x2 M150
Set up the separating strip+
­ Make a layer of 10cm –thick medium-grainedhot asphalt concrete:

Blow out dust, sprinkle tack coat with the standard of 0.5kg/m2+

Hot asphalt concrete layer+ 10cm-thick medium grain

1.7. Make the layer of 5cm thick fine-grained asphalt concrete
­ Spray tact coat with the standard of 0.5kg/m2
­ Spread the layer of fine-grained hot asphalt concrete on a half of road section

Do the same as a half of remain section
1.8. Demolition of curbstone concrete, old separating strip, erecting ground edge, planting weeds

For the old curbstone: use crane to dig and take to other allowed places

Erect ground edge: soil is carried and poured near the edge by trucks, and made smooth by the excavator and worker, pressed by the rammer, weed is planted by workers.
1.9. Finishing Work:
­Maintenance  

Road surface sanitation, route painting

Install signs and instructions
1.10. Construction warranty:
The construction is under 24 - month warranty and accounts for 3 percent of general cost estimate under Article 29 of Resolution No.209/2004 NĐ-CP on December 16, 2004 issued by the Government. Construction unit commits to repairing and overcoming structure failure (if have) under warranty.

2. Construction arrangement project:
a. Choose a means of construction:
First, it is legitimate to choose a means of construction for work items representing in design document and work cost estimate, Tenderer uses the result of design profile and cost estimate to make a plan for construction progress.

For asphalt concrete using truck, iron wheel rollers, tire rollers

b. Choose method of building:

The company chose method of building step by step, finishes one-by-one construction and checks the quality, then build next one. 

The company arranges a building team ranging from digging road foundation to implementing stabilized aggregate course. When making two edges, we use fence at two directions to separate construction area from moving vehicle area.

­After finishing that work, we will execute the main road.
­We will work at night in case the construction need completed on time.

3. Make 10cm thick layer medium-grained asphalt concrete:
Applied standard: build, check and take over the layer of asphalt concrete based on the building and checking process of asphalt concrete road surface 22 TCN 249-98.
After making stabilized aggregate course soundly as demanded in design, we continue to build 10cm-thick medium-grained asphalt concrete.

a. Warping Compensation:
Flatten the surface of stabilized aggregate course by grade aggregate from 0 to 4mm.

b. Make clean the surface of stabilized aggregate:
Let workers sweep and make clean the surface of grade aggregate

Clear away dusty noodle of grade aggregate, waste during construction on the surface.

Use air pressure machine to clear dust on grade aggregate’s surface

Remove noodle rock

Dust blowing machine
c. Sprinkle tack coat with the standard of 1kg/m2:(emulsions)
After finishing stabilized aggregate course, the unit will check and take over the construction and allow to spray emulsion.

Emulsion transported by the special purpose truck can keep high temperature.

Emulsion is sprinkled from 4 to 6 hours in advance to finish separation before placing hot asphalt concrete. The surface of crushed rock to sprinkle emulsion is tested for glueyness.

d. Cover 10cm thick medium-grained hot asphalt concrete:
Implement the layer of asphalt concrete when building the previous layers exactly.

 Preparation Works:
 Use piles and strain string to identify position and elevation laying at 2 sides of road surface which is shown in design.
 Use rectangle steel bar to limit laying trace.

Asphalt Concrete Transportation:
 Use dump truck to transport asphalt concrete mixture

Identify the number of trucks and appropriate distance for truck to stop

 Truck body has closed bottom, have enough 4 sides + clean body.

 Need a canvas to cover in case of strong wind or rain

Spread asphalt concrete:
 Scatter asphalt concrete by single purpose machine, sometimes made by hand in narrow path.

Start up spreader before working from 10 to 15 minutes so as to assure machine, screw, and routing table work well, and to heat up ironing plate.

The truck carrying the mixture backs forward to the funnel of spreader, the wheel relatively and deliberately exposes to two roll bars of spreader. Then handle truck body to pour the mixture of asphalt concrete into the middle of spreader’s funnel. The spreader pushes truck with spreader forward

Depending on the thickness of asphalt concrete, control the speed of spreader.

Adjust elevation of spreader to equal pressing elevation multiplied with coefficient, watch and adjust elevation of hot asphalt concrete layer when spread by marked iron stick.

The mixture of hot asphalt concrete is usually soaked up two – thirds of the height of spiral conveyer.    

During spreading, the rammer bar of spreader always operates.

 As for down and cross joint, before placing a new layer, the part exposing to old layer is cut straightly and covered with tact coat to assure that the new layer sticks with old one.

When spreading, workers with tools following the spreader to do some tasks such as:

Make excessive the mixture of asphalt concrete along joint into thin layer, flatten convex and concave before compaction.

 Remove, add to local convex and concave on newly spreading asphalt concrete layer.

Spray oil to prevent asphalt concrete from sticking with roller’s wheels

+ Traces due to ceasing construction: the spreader fails to load beyond placing track from 5 to 7m. Use a hot rake, hot iron rake to scatter over the final edge of spreading track until it is thick enough and becomes a straight line, perpendicular to the heart of road.

+ Check the temperature before spreading by thermometer, temperature is not lower than 130oC.
 Supervision of asphalt concrete construction usually begins from blending station to site such as:

Check the accuracy of mixing machine, measure system 

Evaluate technical standard of inputs for mixture creation.

Control the quality of asphalt concrete when leaving mixing station.

+ Check the quality of material whether it is divided after transportation.

+ Check the heart of pile’s position and piles restricting spreading tracks, straining strings.

­ Compact AC course:
Roller is used: 16T pneumatic tyre roller combined with 8T and 12T hard tyre roller.

+ Make smooth as soon as the spreader finishes AC mixture courses. Try to finish compaction as the mixture is under high temperature to work well. The most temperature for compaction is 130-140oC. When temperature is lower than 70oC compaction fails.
+ 8T hard tyre roller is used in the first compaction with the speed of 4-5km/h, 16T tyre roller is used in the second time with the speed of 2-3km/h, 12T hard tyre roller is used in the final compaction with the speed of 1.5km/h.
+ Use anti-bonding oil to spray on roller’s tyre to prevent AC from sticking with roller’s tyre.

+ When roller chang its direction, operation should be careful and softly. The roller does not stop on AC course which is not compacted and under hot temperature.

+ Spreading in case of rain:
Ask mixing station for ceasing

When AC course is pressed as firm as two-thirds of requirement, keeping compacting in rain until it is hard enough.

When AC course fails to reach two-thirds of requirement, stop compressing and move the mixture out of pavement. When the pavement is dry, resume spreading.

 To overcome the difficulties due to bad weather, we need distribute properly the length of spreading, choose short spreading track when the weather is unfavorable.

4. Check and take over AC pavement:

+ Geometry size:
the width of pavement is measured by steel ruler.

The thickness of spreading course is checked and taken over in line with sides by leveling AC course compared with leveling data of corresponding points at foundation layer (or by lower AC course)

The slope of pavement is measured by direction perpendicular to the heart of pavement, from heart to edge (if 2 roofs) and roof to roof (if road have one roof). The measuring point at edge is from 0.5 m. The distance between 2 points is not over 10cm.

Geometrically typical deviation of pavement is not over restriction.

Vertical slope is checked by leveling at the points along the heart of pavement.

+ The smooth and flat degree is measured by 3m ruler.

+ Skid resistance of pavement is checked by scattering sand under 22TCN 278-2001.

+ Density of compaction:
The coefficient of compressing of AC pavement course after construction is not lower than 0.98.

Every 200m of two - lane road or every 1500m2 of AC pavement, we drill a set of 3 holes 101.6 m in diameter to test the coefficient of compressing, use devices which causes no damage.

The observed quality of joints is straight, not poked surfaces, and has no cracks.