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“DIAMOND GRINDING OF CONCRETE PAVEMENTS”

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OBJECTIVES:-TO UNDERSTAND THE PROCESS OF DIAMOND GRINDING OF CONCRETE PAVEMNETS

TO BE AWARE OF THE VARIOUS ADVANTAGES OF ADOPTING DIAMOND GRINDING

TO EVALUATE THE EFFICIENCY OF DIAMOND GRINDING IN

1. IMPROVING SKID RESISTANCE2. REDUCING NOISE EMISSION

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WHAT IS DIAMOND GRINDING?

Pavement preservation technique

Restores rideability by removing surface irregularities

Significant improvement in the smoothness of a pavement

Considerable increase in surface macro-structure and consequent improvement ina) Skid resistanceb) Noise reductionc) Safety

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WHY GRIND CONCRETE PAVEMENTS??

Poor quality and rapid deterioration of concrete pavements

Resulted in an increase in Increase in road accidents

their maintanence expenditure High mortality rates

Hence we need to adopt efficient pavement preservation techniques that correct a variety of surface imperfections on

concrete pavements.

Diamond Grinding is one such technique

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OTHER EFFECTS OF DIAMOND GRINDING

Reduces pavement liftImproves drainage Reduces the potential for hydroplaning

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PROCESS•Involves removing a thin layer at the surface of hardened PCC using closely spaced diamond saw blades

•Blade assembly is run at a predetermined level across the pavement surface, which produces saw cut grooves

•The diamond blades are composed of industrial diamonds and metallurgical powder

Enlarged schematic representation of cross section of diamond ground surface

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DIAMOND SAW BLADES

SAW BLADES ASSEMBLED TO FORM CUTTING HEAD

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Typical configuration for grinding

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DIAMOND GROUND PAVEMENT SURFACE

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APPLICATIONS•Improve the skid resistance and evenness of concrete pavements

•Improves or corrects surface imperfectionsi. faulting at joints and cracksii. built-in or construction roughnessiii. polished concrete surfaces exhibiting inadequate

macrotextureiv. wheel path rutting caused by studded tyresv. unacceptable noise levelvi. slab warping caused by moisture gradient and

construction curlingvii. inadequate transverse slope and splash and spray

reduction

•Texture pavement inorder to make them suitable for suitable for recreational activities such as bike riding or roller skating.

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ADVANTAGES1) Provide smooth surface 2) Reduced road noise 3) Removes faults 4) Enhanced surface texture and skid resistance 5) Reduce accident rates6) Does not significantly affect fatigue life7) Diamond-ground surface is nearly always dry8) Does not raise the pavement surface

elevation9) Can be accomplished during off-peak hours 10)Cost advantage

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DESIGN CONSIDERATIONS

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• major distresses of the pavement should be repaired

Thoroughly evaluate the existing condition of the pavement,. Pavement evaluation is done in a multi-step process.

i. design and condition data is collectedii. data is then evaluatediii. evaluation data is used to design a CPR strategy

A full CPR job can restore structural capacity to levels near those of new construction.

Diamond grinding restores ride by blending the old slabs with new repairs into a uniform profile

Pavement joints resealed after diamond grinding

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FACTORS TO BE CONSIDERED WHILE SELECTING A DIAMOND

GRINDING PROJECT• Actions should be taken to alleviate drainage or erosion

•Transverse slab cracking and corner

•Joints and transverse cracks

•The hardness of the aggregate and depth of cut has a direct relationship on the cost of the diamond grinding.

•Significant slab replacement and repair

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EQUIPMENTS Produced by running a series of saw blades which are gang-mounted on a drive shaft over the concrete surface

The depth of grinding is between 3 and 5 mm

Diamond-tipped grinding segments, variable in width are situated at the edge of the blades

The separation of the blades is set by spacer disks and is at most 3 mm.

Diamond ground texture consists of grooves and land areas.

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• Most important aspects of a grinding machine weight of the machinethe horsepower available to the grinding headthe grinding head

• Front wheels pass over a bump or fault, which is then shaved off by the cutting head

• Rear wheels follow the smooth path left by the grinding head

• Cutting head width -> 910 - 970 mm

• Spacing of diamond blades -> 164 - 194 / m of shaft

• Uses water to cool the cutting head

• Contain on-board wet vacuums to remove slurry

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RANGE OF VALUES (mm)

HARD AGGREGATE (mm)

SOFT AGGREGATE (mm)

GROOVES 2.0-4.0 2.5-4.0 2.5-4.0LAND AREA 1.5-3.5 2.0 2.5HEIGHT 1.5 1.5 1.5NUMBER OF GROOVES /m

164-194 174-194 164-177

Recommended dimensions for hard and soft aggregates:-

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CONSTRUCTION

Traffic ControlField Operations

Final Surface Finish

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TRAFFIC CONTROL

Do not require shutting down adjacent traffic lanes An approved traffic control plan is essential Several machines works together

(large projects) Contractors use only one machine and several passes for small projects The maximum overlap between passes should be 50 mm

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FIELD OPERATIONS

Should begin after all repairs

Should be performed continuously

Should begin and end at normal to the pavement centerline

Grinding is always longitudinal

Should be performed across the entire lane surface

Spot grinding is not recommended

Grinding will provide a positive lateral drainage

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FINAL SURFACE FINISH Pavement surface shall be uniform in appearance

Land area between the grooves shall be between 1.5 &3.5 mm

Peak of ridges shall be 1.5 mm higher than bottom of grooves

Pavement surface measured using

A straight-edge requirement may be used to control bumps

Transverse slope of the pavement shall be

Transverse joints and random cracks shall be visually inspected

Misalignment of the planes shall not exceed 1.5 mm per meter

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COMMON PROBLEMS AND SOLUTIONS

Light vehicles and motorcycles

experience vehicle tracking

Reduce the spacing between the

blades.

Some areas are left without diamond-

ground texture

If the untextured area exceeds project

specifications, regrind it

Large amounts of concrete slurry are

left on pavement surface

Stop grinding operations and check the

vacuum unit and skirt surrounding the

cutting head

Concrete fins fail to break off Reduce the spacing between the

blades

PROBLEMS SOLUTIONS

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EVALUATION OF SKID RESISTANCE ON DIAMOND GROUND PAVEMENTS

diamond grinding increases skid resistance and safety

Friction factor, f=F/LSkid Number: SN=100(f)

where: F=frictional resistance to motion in plane of interfaceL=load perpendicular to interface

friction resistance of most dry pavements is relatively high

The number of accidents on wet pavements are twice as high as dry pavements

Typical Skid Numbers

Skid Number Comments

<30 Take measures to correct

≥30 Acceptable for low volume roads

31 – 34 Monitor pavement frequently

≥35 Acceptable for heavily travelled roads

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CASE STUDY 1(DoT ,TEXAS)

DG utilized improve skid resistanceEleven DG projects were studied

RESULTS ARE:-• IRI(I reduction of  0.95  m/km (40%)• Oldest DG section maintained an IRI reduction of about

36% after 8 years• Skid number (SN) increased by 5.6 (30%)

• IRI increases by approximately 0.03  m/km each year& SN decreases 2.0

• After DG, the crash accidents had reduced by 62 and 46% for fatalities and incapacitating injuries

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EVALUATION OF NOISE EMISSION OF DIAMOND GROUND PAVEMENTS

CASE STUDY 2(BOING ACCESS ROAD ,WASHINGTON)

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RESEARCH IN GERMANY

The relationship among surface texture, concrete composition and noise emission

Composition of the concrete, the thickness and spacing of the diamond blades

Texture characteristics and air flow resistance of textured surfaces

Vibrations of tyres and the aero-dynamic processes

AN ONGOING LABORATORY RESEARCH IN GERMANY (FEDERAL HIGHWAY RESEARCH INSTITUTE) INVESTIGATES :

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LABORATORY INVESTIGATIONS

Noise emission was lower for segments widths of 2.8mm than for 3.2 mm

Noise emission is lowest for surfaces produced with very low spacer widths

No effect of concrete composition on the textural properties

Concrete produced with rounded aggregate possessed similar textural properties, noise emission and fine roughness to concrete made with crushed aggregate.

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CONCERNS Faulting reoccur (load transfer is deficient)

Does not correct any structural problems (e.g., slab cracking) or material problems (e.g. reactive aggregates).

Reduces pavement thickness (pavement fatigue performance) [200-230 mm]

Not all concrete pavements are good candidates for diamond grinding.

May not be sufficient in all cases.

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CONCLUSION

Improves skid resistance and reduces the risk of hydroplaning (safety)

Investigations have shown that diamond grinding is a good alternative to exposed aggregate concrete for the production of low-noise pavement surfaces

Experimental findings and researches indicate that diamond grinding is a viable and cost-effective rehabilitation measure when properly applied

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REFERENCES

•Jens Skarabis and Ulrike Stockert (2015). Noise emission of concrete pavement surfaces produced by diamond grinding 2 ( 2 ) : 8 1 - 9 2

•Chen D and Hong F (2015). Long-Term Performance of Diamond Grinding. 29(1) pages 12-25.

•Caltrans. (2013). Diamond grinding and grooving- California Dept. of Transportation (Caltrans) Vol 1,Issue 1

•Drakopoulos and Schmiedlin. (1998). Crash experience on tined and continuously ground Portland cement concrete pavements, Washington, DC Pages 140–146

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•Stubstad, and Tabet (2005). The effectiveness of diamond grinding concrete pavements in California . 73, 307-325

•Rao, and Darter, M. I. (1999). The longevity and performance of diamond—Ground pavements, research and development bulletin RD118, Portland Cement Association, Skokie. 112.

•Federal Highway Administration, (2004) Pavement preservation design and construction of quality preventive maintenance treatments, National Highway Institute Course 13-20.

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THANK YOU….