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Cement a Good Additive for Durable Economical Road

• By • P L Bongirwar, M Tech, FNAE • Former Principal Secretary PWD • Advisor Larsen and Toubro • roadcondition.jpg • potholesrevised0001.pdf Usage of Cement • Cement is oldest popular and economical additive • Cement has tremendous potential in construction • Cement is extensively used in Building and construction • However use of cement for road construction is limited even though has tremendous potential • Improvement in has enabled us to get cement concrete of very high strength, early strength. Self compact concrete requiring no vibration etc • Usage of cement can create more durable roads requiring least maintenance hence justifiable on criterion of life cycle cost • Introduction of new equipment, additives , and new research has narrowed d the gap between bituminous road and concrete roads in terms of initial cost

Infrastructure Development of NE region • Honorable Prime Minister has announced that GOI intends to spend 1 lakh crores in next three years in NE region for road improvement • We need to develop new which allow local marginal materials • By adopting cemented base and sub base we can use 75% of marginal materials • Paneled concrete with base and sub base of local materials and CRCP can address the problems of steep , sharp curves and heavy rainfall for hilly areas Cement based Technologies • Sub grade improvement using cement stabilization techniques • Cemented layer to get permeability of 350m/day • Cemented base to reduce cost • Continuous • Precast Pretensioned panel concrete technology • White topping • Paneled concrete technology • Self Compact Concrete for Village Roads • Cement grouted Bituminous mix • Grouted seal coat for conventional carpe • Paneled concrete technology to revive old damaged village roads • Controlled low strength material for trech filling Urban Road Problems

• Urban Bituminous roads suffer damages in Monsoon in the form of and heavy damage to surface • This leads to slowing of trafic,accidents and public criticism • Heavy expenditure on temporary and permanent repairs to give relief leads to public criticism • Discomfort to public has lead to petition in court and action taken by local authorities being monitored by court Causes of Damage To Urban roads • Flooding of roads due to inadequate storm water system • being virtually absent the sub surface drain do not function effectively • The standing truck causes surface cracks allowing water to enter damaging the road crust • Frequent braking action and wearing coat not being designed to sustain heavy tractive frequent force causes damages specially at junction • Not able to follow speciation for DBM /BC in respect of maintaining temperature at laying and compaction • Absence of god quality bitumen • Bituminous treatment is not fuel spillage resistant • Failure of research institutes/academicians to evolve specifications to suit urban problems

Types of Road Pavement

Pavement

Flexible Rigid

Composite Flexible CGBM CRCP Jointed Paneled

CGBM-Cemented Grouted Bituminous Composite-Cemented Base and flexible Wearing Coat CRCP-Continuously reinforced concrete Pavement Flexible Pavement Subsurface drain-Important recommendation • An effective Subsurface drain is a must in stabilized sub base technology and all categories of pavement • 350 m per day is recommended value against about 20m by traditional GSB • As per AASHTO if pavement system is saturated only 10 % of life ie one month in a year it looses life by 50 % • Either Bitumen bound (2 % bitumen) for 4 or voided concrete is recommended • Due to reduced thickness of bituminous layer layer the same would match cost wise with GSB • For urban area due to low embankment and adjoining properties this is difficult to achieve • Can we drain subsurface water in sewer underground drains ? Study would show that it is economical Flexible Pavement-Options available

BC with VG 40 IRC 37 gives BC with VG 40 thickness of BC with VG 40 DBM with VG 40 different DBM with VG 40 DBM with VG 40 RAP stabilized with layers for emulsion/foam different sub WMM WMM bitumen grade and Cement Bound Cement Bound designed GSB drainage layer Drainage layer Cemented GSB Sub grade Cemented GSB Sub grade Top BC can be Sub grade replaced by By increasing CBR from 10% to 15% by cement stabilisation cost Gap Graded reduction of 10% can be achived High Binder CMHB mix Due to cemented base and subbbase 15% cost reduction is possible Jointed Rigid Pavement • Advantages i. Reduced recurring maintenance cost and preferred by public for urban roads and village roads ii. Lifecycle cost for even 15 years compared to flexible pavement less- Already observed in MPE Leads to fuel saving iii. Not dependable on imported bitumen Disadvantage i. Riding quality inferior compared to bituminous road, higher ii. High-speed drive leads to higher temerature and if tyres are worn out the incidence of tyre bursting iii. Require higher supervision, better compaction for embankment and difficult to repairs. Cannot open to traffic immediately iv. Sensitive to overloading and temperature Higher initial cost compared to bituminous road Deficiencies can be addressed by new technology and new material Continuous reinforced concrete roads CRCCRCP 3025 Rs per Square meter Concrete Jointed Road 3070 Rs square meterP 3025 Rs per Square meter Concrete Jointed Road 3070 Rs square meter In this technology joints are virtually eliminated and steel reinforcement is given and thus riding quality improves A bituminous overlay also is recommended which improves the riding quality and substantially reduce noise pollution The UK design philosophy allows reduction in thickness hence cost is comparable to jointed rigid pavement Several kilometer of CRCP roads are constructed in Pune in hilly terain,steep grade, heavy rainfall and trucks carrying heavily loaded materials Paneled concrete

Paneled concrete-1900 Rs/sqm Flexible Pavement-1927 Rs/sqm

Can be adopted for new road or existing bituminous road carrying heavy traffic Requires closely spaced joints of max 1.5 m*1.5 m Self compact concrete, thin joint and other construction techniques would improve the riding quality May not require renewal or strengthening overlay Revised SP 76 has fully covered Funding for applied research for improving the technology is needed Precast Pretension panels

Advantages-Minimal mobilization of from site-to-site with no capital investment for automatic paving equipment, dump trucks, spreaders, finishers, etc. Controlled process in fabrication of panels. Fabrication and finishing of concrete panels take place at the different precasting site. Better concrete product with greater achievable strength, minimal variation in strength, and a better concrete curing method that can assure quality concrete. Steady production of panels, up to 24 hours a day, with no delay during the rainy season. 7 Thinner concrete pavement in comparison to Jointed Plain Concrete Pavement (JPCP), which would reduce the cost of construction. Post-tensioning wire strands are relatively cheap. Better construction sequences once the pavement base or sub base is in place. This will eliminate issues with dowel baskets, tining, in-place curing, etc. Long-lasting and durable pavement.

Rigid Pavement • Jointed Rigid Pavement • Continuous reinforced concrete pavement with and without BC overlay • Paneled concrete-Concrete overlay with closely spaced joint-for new Road/Existing Road • Low Volume Concrete Road a)up to 50CVD,b)50 to 150 CVD c)150 to 450 CVD • Grouted BM-Voided Bituminous Macadam to be grouted with high strength M40 or above high grade Thickness of different layers can be concrete worked out based on designed DLC traffic, grade of concrete and joint spacing WMM GSB In paneled concrete panel size Sub grade could be 75*75 to 175*200 CM Paneled concrete/White toping • The technology of putting concrete overlay on existing bituminous surface called white topping/paneled concrete is getting widely accepted • More than 100 km of such roads completed in , Thane Nagpur and Pune • As maintenance cost is minimum this has become accepted mode. In Pune it is decided to do all roads below 12m width with this technology only • All design and construction methodology is covered in SP 76 • You have to asses the strength of existing road and design the thickness of overlay which may workout to 12 to 15cm Panele size is reduced to 1.25*1.25 m hence temperature stresses virtually is absent hence reduced thickness Paneled concrete for Heavy density road

• Even though the is developed for urban low volume road as overlay over the existing bituminous road ,but this can be adopted for heavy density roads as as for new roads where properly designed GSB, WMM and DLC can be given as base • The revised code of SP 76 describe the technology fully • It is seen that cost of flexible pavement for 100MSA and paneled concrete is same .As paneled concrete can be designed for 30 years it will not require renewal or overlay and hence overall it will be much economical

Paneled Concrete for Heavy density roads • There are several examples of adoption of this technology for heavy density roads • ring roads and several roads in Pune such as Shivaji Nagar bus stand are few examples • In Nagpur outer ring roads two trial stretches each of 250m for totally new road are laid and found to be successful • Prove ideal in poor drainage conditions and specially with very low embankment specially in urban situations • Concrete technology is fully developed to get strength of M 50 and above in 24 hrs and hence road can be opened in 48 hrs

Paneled concrete

Paneled concrete-1900 Rs/sqm Flexible Pavement-1927 Rs/sqm

Can be adopted for new road or existing bituminous road carrying heavy traffic Requires closely spaced joints of max 1.5 m*1.5 m Self compact concrete, thin joint and other construction techniques would improve the riding quality May not require renewal or strengthening overlay Revised SP 76 has fully covered Funding for applied research for improving the technology is needed Summary of stresses Economics

50mmBC 200 mm Paneled Concrete M40 110 mm DBM 75 MM BM/ 100mmDLC 250mm WMM 250 mm WMM 200mm GSB 200mm GSB 500 mm Sub grade 500 mm sub grade

100 MSA ,1927 /sqm >200 MSA 1900 /sqm

BC 10100,DBM 8600,WMM 1120,GSB 980,M40 5000-Per Cub m Over View of Finished Rigid Pavement Bus Stand TWT Pune

Case Study-Mankar Town urban road,Burdwan district,WB • Urban roads generally have low embankment and poor drainage conditions • Blacktopped roads therefore suffer heavy damages • Short paneled concrete roads could be cost effective durable pavement Exiting Road Typical construction

150 mm M40 grade of concrete with panels of 1m*1m and joit upto 50mm depth 100mm M 10 base Existing road Completed Road Trial Stretch planned by Prof Pande

!80mm Thick M40 grade paneled concrete with panels of 1m*1m 2kg/cub me recorn fibres or 1kg of Polyproplene per cubic meter 200GSM for bond braking 150mm cemented drainage layer with 2.25 % cement 7 MPa at seven days 150mm cemented filter layer with 2.5 to 3% cement 3 MPa at 7 days

Maximum flexural stress is 2.72 MPa at the end of design period Adoption of Self compact concrete for village roads

SCC with 290kgcement,200kg fly ash with additive having cost of 1900 per cubic meter Eliminated need of vibration, PVC strip eliminated need of Joint cutting and sealing Investment in equipment 9 Lakhs Controlled low Strength Material -CLSM CLSM-Definition

CLSM is a self-compacted, cementitious material used primarily as a backfill as an alternative to compacted fill. ACI:116R: Defines CLSM, as material that results in a compressive strength of 8.3 MPA or less CLSM should not be considered as a type of low strength concrete but rather a self compacted backfill material.

Controlled Low Strength Mateial- Potential application • Back filling in -Trenches made to lay new services are backfilled by same materials Being narrow compaction not possible hence settles continuously requiring frequent maintenance Trenches prposed to be filled in with CLSM which is highly self leveling flow able grout and does not require compaction It fills into side crevices offering of sides to support load hence does not settle • Side strips of concrete roads made bituminous or paver block surface for ease to lay future services Due to improper compaction of backfill material after laying services the side strips get totally distorted and hence not useful to traffic Base in both cases proposed with CLSM and restoration after laying services by CLSM

Mix Design

Material Qty-KG/Cub M Brand Cement 50 FlyASH 200 PARAS Micro Silika 0 20mm 313 10mm 364 R 0 Crushed Sand 567 Water 195 Admixture 1.5 Mlab 24+CF b Density 1692 Lab trial-Initial flow Trench filling -Kothrud Conclusion

• Conclusions • 1. Panelled concrete pavements can be a good alternative for reducing the cost of concrete pavements for built up areas, rural roads, bus bays etc. • 2. Stresses are reduced drastically in concrete pavements with panels of size 1.0 m × 1.0 m. • 3. If alternative route can be arranged, this type of pavement is very easy to construct with much higher durability than Mastic surfaced bituminous pavement; and the serviceability is expected to be same as conventional rigid pavement at much lower cost. • 4. This technology can emerge as a good long-term solution to the perpetual maintenance problem of the roads with poor drainage.

Cement Grouted Bituminous Macadam • Urban roads get heavily damaged mainly in rainy season due to frequent braking action • Transverse tensile force caused due to heavy braking force is the cause of leakage of moisture and hence damage • We need surface which is water tight and resist frequent tractive force • It is difficult to maintain temperature at laying and compaction resulting into inadequate compaction Cement Grouted Bituminous Macadam • Tradiotnal Wearing coat a) BC with 50 mm 550 Rs square meter b) Mastic asphalt 700 Rs Sq meter c) Paver laid Mastic 1200 Rs sq meter d) Concrete top surface 1600 Rs sq m e) Paneled concrete 900 Rs Sq m f) Paver block on top 800 Rs sq m Cement grouted bituminous Macadam consist of 40 mm Bituminous Macadam with 3.5% bitumen in which voids are filled with high strength grout making it water tight and resistant to tractive force Cost of CGBM could be 540 to 610 Rs per sq m CGBM Technology • In this technology on a voided bituminous mix containing 25 to 30 % voids a highly flow able grout having strength of M 40 is poured • The grout flows into voids due to gravity and make tight and also enhances properties of mass • Surat Municipal Corporation adopted for last ten years and completed more than 100 Kilometer and are not having any potholes • New IRC guidelines recommend up to 30 MSA and for renewal coat and found economical at least by 10 % compared to fllexible pavement Cleaning with compressor BM laying and Compaction Grout preparation and pouring Grouted Seal Coat over 20 mm Carpet Gradation for carpet • Normal gradation for carpet I. 2/3 material passing through 22.4 and retained on 11.2 II. 1/3 material fully passing through 13.2 and retained on 5.6 mm sieve The above provision changed to create more voids 100 % passing through 22.4 and fully retained on 11.2 mm sieve High strength flowable grout used instead of bituminous seal coat

Rolling after pouring grout

Metalled and heavily damaged village roads

More photos of Amravati Finite Element Analysis

Thickness 50mm Thickness 75 mm Concrete 50/75 mm Panel size Edge Panel Edge Stresses size stresses WBM=150mm,E 0.5*0.5 6.59 0.5*0.5 3.87 250 Mpa 0.75*0.75 8.28 0.75*0. 5.65 75 Sub grade 150 1.0*1.0 8.34 1.0*1.0 6.30 mm ,E=100 Mpa 1.2*1.2 8.42 1.2*1.2 6.49 Sub grade 8% CBR e50 Mpa Economics of Grouting Technology Case1 Case2 Case3 Case a1 Casea2 Case a3

Panel size 75*75 100*100 100*100 75*75 100*100 100*100 Thickness 75 100 75 75 100 75 Grade M30 M30 M40 M30 M30 M40 Flexural 4.2 4.2 4.9 4.2 4.2 4.9 strength Actual srtr 4.1 4.05 4.6 4.1 4.05 4.6 WBM QTY 213.75 285 213.75 213.75 285 213.75 Grout Qty 53.45 71.3 53.45 64.13 85.5 64.13 CostGrout+ 4.67 5.37 4.65 5.28 6.17 5.31 Strip Cost /sqm 197.6 226.8 196.4 219 257 221 Grout rate in Rs/Cub m M 30- 5661 , M40 6201 Grout Mix Cement 42%,Flyas 22%,Crushed sand 22% Admixture 0.6%,Hdpe Strip 18 R/m Road Length 750m,width 3.75m Important stages of Lab Expt Grout Cubes and Cores

PMGSY (Grout Mix)

Flow retention (min) Compressive Strength (28 days) Cement Total Crushed Admixture Dosage Date G2 (%) G3 (%) Flyash Free W/C (OPC ACC %) Water.(%) Sand(%) 1 (bwb%) Cube strength Core strength 5 60 (50 mm x 50 mm) (70 mm Dia) 14/01/2014 50.0 50.00 42 22 0.22 15 21 Glenium 51 0.60% 800 750 77.57 72.2 41.89 39.78 Development of grout

• Technology would be economically successful if high strength flow able grout at economic cost is developed • Quantity of grout is function of voids and thickness of layer to be grouted Both can be controlled to reduce cost • A grout to develop cube strength of M60 developed • Cost of grout for core strength of M 30 5600Rs/cubic meter and For M 40 6100 Rs per cubic meter Trial Stretch of grouting technology

By P L Bongirwar • A small road of about 80m as trial stretch in Vasai Taluka in Thane district is done • Carry lot of building material trucks as ,sand,crushed aggregate etc

Removing deficiencies of Concrete roads • Riding quality, noise pollution and tyre bursting-Adopt specially designed 25 mm Open graded bituminous overlay • Early opening-A specially developed high grade concrete is developed which can achieve M60 strength in 24 hours • Improving surface-Adopt self compact concrete to ensure proper dense concrete and surface in line and level • Joint improvement-Reduce joint width, use recompressed seal rubber, cold sealant-Improve riding comfort • Cost reduction-Adoption of high volume fly ash and developing new additives, Two lift concrete • Technology for precast pretension panel to be encouraged and a tender for 10 kilometer be invited Topics for research on Concrete Roads • 1) Behavior and design principles of CRCP concrete • 2) Voided DLC as a base for new high density concrete with paneled concrete • 3) Low strength concrete DLC and its effect on rigid pavement behavior • 4) Cement grouted bituminous macadam • 5) High volume fly ash concrete for road pavement • 6) Review of specifications for road construction if the base is rocky • 7) Use of polymer fibers and steel fibers for improvement in concrete properties • 8) Evolving new fatigue equation in fiber concrete as it improves the ductility • 9) Stresses caused due to temperature and temperature variation along depth • 10) FEM model for rigid pavement and panel concrete • 11) Evaluation of fatigue life of different layers • 12) Bituminous overlay over concrete pavement • 13) Design and construction philosophy for prestressed precast concrete panels • 14) stabilized soil base instead of concrete DLLC • Outcome of above research would not only reduce cost, material consumption but would remove the deficiencies of present technology which will lead to better acceptability of technology

Conclusion and Recommendation for CGBM • Cement Grouted Bituminous Mix Technology is econmical,easy to adopt and found effective by Surat Municipal Corporation • There is need for developing better construction technology and equipment to improve quality • Proper Quality assurance manual, testing procedure,spefication inclusion in DSR has to be initiated • Development of dry powder for grout ,encouraging commercial units to produce and equipment for dry uniform mixing with other ingredients has to be taken on priority • Paneled concrete is definitely economical alternate for urban roads for light aand heavy traffic General Recommendations • Virtually no funds are available from Government for applied research/sponsered projects • Trial stretches are not allowed and discouraged • Engineers and Govt departments are hesitant to adopt technologies included in code. We must do more pilot/demonstration projects • Academic institutes are not geared to do research They can not maintain the time In most institutes there is no incentive to academicians • Most of the academic institute do not own modern testing equipments and do not have sources to procure • Cement Industry also are not giving any money for planned research • There is need to develop new equipments to ease in application of these technologies specially CGBM • Equipment is required for thin joint cutting • Detailed working construction specifications as well as quality assurance manual must be prepared for proper implementation