Presentation on theme: "Performance of Warm Mix Technology in The Province of New Brunswick Terry Hughes, P.Eng. NBDOT J. Keith Davidson, P.Eng. & Alain Cormier, P.Eng. McAsphalt."— Presentation transcript:
Performance of Warm Mix Technology in The Province of New Brunswick Terry Hughes, P.Eng. NBDOT J. Keith Davidson, P.Eng. & Alain Cormier, P.Eng. McAsphalt Industries Ltd. CTAA – Moncton - 2009
Outline of Presentation Introduction to Warm Mix Asphalt (WMA) Benefits of WMA Description of WMA Processes used in NB Practical and Laboratory Review of NB Projects and mix designs Environmental Data Field Observations and Comments Conclusions
Introduction What is Warm Mix Asphalt (WMA)? Asphalt Concrete that can be mixed and placed at lower temperatures than conventional HMA while maintaining the original physical properties.
Environmental Benefits of WMA The green shift Kyoto Accord targets (Canada); Its politically correct!! Global Warming Stricter environmental rules; plant permit Emission Reductions; smog days –SOx = Acid Rain –NOx = Smog, Ground Level Ozone; Green House gas (significantly worse then CO2 for global warming) –VOC = Volatile Organic Compound = Carbon Containing gases; Evapn light ends from oil –CO2 = Green House Gas = global warming –CO Carbon Credits
Practical Benefits of WMA Increased haul distances: –Slower cooling rate & compaction temperatures –Can be heated to regular HMA temperatures to compensate for long hauls w/o oxidizing mix. RAP content without requiring a binder change Thin lift paving $ Fuel $ Consumption; up to 55% Plant Emissions Fumes for workers at paver RTR pick-up; differential temp. is less
WMA is much safer to work with and great for bring your kids to work day!
Practical Benefits of WMA (contd) Decrease Oxidation of mix: –Each 25F decrease in mix temp = 50% less oxidation of the binder. Evotherm binder after 7-10 years of laboratory simulated aging = New HMA binder Studies have shown it to be more resistant to reflective and fatigue cracking. –More testing/trials needed; would depend on underlying crack movement/type
Practical Benefits of WMA (contd) Extend season: cooler weather; night paving –WMA can be heated to regular HMA temperatures to compensate for cool weather Potential for a decrease AC absorption in stone = less AC reqd= $ AC savings $
TxDOT Cores After 1 Year Hot Mix Control Warm Mix Asphalt AC absorption = Wasted AC $$
Evotherm Process 3 Delivery systems: Emulsion: High residue emulsion (typ. 68-70% Residue) Directly from tanker or from AC tank DAT Solution: (Dispersed Asphalt Technology) Injection System Totes or a separate storage tank at HMA plant 3G- Third Generation: AC additive @ low dosage; chemical package Evotherm 3GV Evotherm 3GR Added to tanker at AC terminal; AC tank required at HMA plant
Evotherm Emulsion High residue (typ. 68-70%) Replaces AC; drop-in technology Both batch and drum plants
WMA test results were very similar to HMA: –air voids, density, VMA etc. HMA mix designs can be used for WMA, however a slight AC drop in the design may be required to maintain voids due to increased compatibility and effective AC. Dust adjustment may be required at plant to increase air voids; baghouse dust removal capabilities decrease due to lower mix temps.
Location of Evotherm Emulsion Job on Rte 111, St. Martins ~60 km haul Lafarges Plant Job: - West Section: WMA-D Padding + WMA-D - East Section: Partial Mill + WMA-D - Total WMA-D 1.1km Moncton 1.5hrs
McA Mix Check of Lafarge Rte 111 Mix BlendSourceType D 12.5 mm StoneGrandview30.0% 6.35 mm minusGrandview44.0% Washed SandGrandview18.0% Blend SandBlagdon8.0% Evotherm 58-28 ETMcAsphalt8.82% ** Based on 6% residue Physical Properties HMAWMANBDOT Spec Mixing Temperature °C150130 Compaction Temperature °C13590 N design – Gyrations100 Bulk Relative Density2.3992.376 Maximum Relative Density2.4982.472 % Air Voids3.973.88 % VMA15.416.214.0 minimum % VFA74.175.965 - 75 Tensile Strength RatioAnti-strip Reqd 92.2 No Anti-strip 75 % minimum
Rte 111 Evotherm Emulsion WMA -D Mix Results (McA Field Samples) SampleJMFWMA-1WMA-2WMA-3 Time6:00 am9:25 am3:55 pm DateSept 14Sept 16 Sieve 12.5 mm100.0 9.5 mm95.591.086.990.1 4.75 mm62.757.850.557.0 2.36 mm39.538.728.135.1 1.18 mm25.925.418.224.0 0.600 mm16.715.712.515.9 0.300 mm11.08.68.29.7 0.150 mm22.214.171.124.4 0.075 mm126.96.36.199.6 % Residual AC6.05.495.806.19 Bulk Recompacted Density2.3762.3912.3762.433 Maximum Theoretical Density2.4722.4872.4862.470 % Air Voids3.883.864.421.50 Penetration Recovered Asphalt Cement11693 100 WMA Recovered Pens were 80-86% of original Pen vs. typical 60-70% with HMA ? Outlier
Evotherm Emulsion (contd) Residue Testing on Emulsion: DOT: 74.5%, 77.1%, 77.9 McA: 71.3%, 71.2, 69.2% Emulsion Content @ HMA plant was adjusted to compensate for fluctuation in residue and to meet air voids requirements. NBDOT field testing indicated to dry samples to a constant mass.
Location of Evotherm 3G Job on Rte 106 Moderns Plant Job: - Mill + Base + Seal - 1.5km WMA-B & WMA-D - 1.0km HMA-B & HMA-D ~29 km haul
Mix Design Data Rte 106-Modern Construction BlendType BType D Mix HMAWMAHMAWMA 25.0 mm Stone43.743.8 12.5 mm Stone24.424.5 6.3 mm Fine46.546.662.262.3 Blend Sand4.8 7.6 PG 58-285.05.8 PG 58-28 – 3G Evotherm®4.85.6 Physical Properties Mixing Temperature °C150130150130 Compaction Temperature °C135-140120135-140120 N design – Gyrations100 Bulk Relative Density2.4012.3982.3992.395 Maximum Relative Density2.5012.5042.4962.495 % Air Voids4.04.253.914.0 % VMA14.1614.0515.7115.45 % VFA71.869.875.174.1 AC lowered to maintain voids
Rte 106 Fuel Consumption Batch Plant No 2 Fuel 8000 lb Batch WMA-B ($/MT) WMA-D ($/MT) AC Cost-1.5 Fuel Cost-5.94.6 Evo 3G Premium+2.4+2.8 Overall Saving vs. HMA$5/MT$3.3/MT MixFuel Consumption Litres/tonne Fuel Saving % Warm B mix4.55852% Hot B Mix9 – 10 Warm D Mix5.64840% Hot D Mix9 - 10
Rte 106 – Compaction Results Mix TypeCompaction Range (%) Average (%) Warm B Mix92.7 – 97.994.4 Hot B Mix94.2 – 95.795.0 Warm D Mix94.0 – 95.294.6 Hot D Mix92.3 – 95.893.6
Rte 106: Base Mixes DOT Test Data Mix TypeHMA –BWarm Mix – B SampleJMF1212 Time9:30 am8:00 am4:40 pm9:00 am DateJuly 14July 15 July 16 Sieve 25.0 mm100.0 19.0 mm94.893.093.594.794.0 16.0 mm86.285.587.088.487.1 12.5 mm75.979.480.979.8 9.5 mm66.570.172.368.871.2 6.3 mm55.557.159.555.758.1 4.75 mm46.547.950.846.250.3 2.36 mm30.332.535.731.734.2 1.18 mm188.8.131.522.724.1 0.600 mm16.317.919.717.618.4 0.300 mm10.610.511.810.711.0 0.150 mm184.108.40.206.46.2 0.075 mm220.127.116.11.74.4 % Asphalt Cement5.0/4.85.035.164.855.12 Bulk Recompacted Density2.3982.3862.4032.4052.411 Maximum Theoretical Density2.5042.4982.4962.5032.505 % Air Voids4.254.483.733.923.75 % VMA14.0514.7214.2313.8413.87 % VFA69.869.473.871.773.0 WMA and HMA results are both very consistent with JMF
Rte 106: Surface Mixes DOT Test Data Mix TypeHot MixWarm Mix SampleJMF112 Time8:00 am 12:00 pm DateJuly 18July 17 Sieve 12.5 mm100.0 9.5 mm94.795.892.288.6 6.3 mm74.6 72.371.4 4.75 mm62.563.662.260.6 2.36 mm40.542.540.138.9 1.18 mm28.329.027.426.1 0.600 mm21.5 20.319.1 0.300 mm13.313.012.411.3 0.150 mm18.104.22.168.5 0.075 mm5.25.7 4.6 % Asphalt Cement5.8/5.65.795.705.60 Bulk Recompacted Density2.3992.3842.4182.389 Maximum Theoretical Density2.496 2.4982.496 % Air Voids3.914.493.24.29 % VMA15.7116.0114.7315.66 % VFA75.171.978.372.7 WMA and HMA results are both very consistent with JMF
Rte 106: SHRP Results on Lab and Field Data SampleBase PGAC-3G Recovered WMA Recovered HMA Spec Tests on Original AC Rotational Viscosity @ 135ºC, Pa.s @ 165ºC 0.290 0.088 3.0 max Dynamic Shear Rheometer. G*/Sin δ, kPa,@ 58ºC @ 64ºC 1.19 0.54 1.0 min RTFO Residue (AASHTO T240) Mass Change, %0.0741.0 max Dynamic Shear Rheometer. G*/Sin δ, kPa, @ 58ºC @ 64ºC 2.55 1.14 2.95 1.30 3.04 1.34 2.2 min PAV Residue (AASHTO R18) ºC100 Dynamic Shear Rheometer. G*x Sin δ, kPa,@ 19ºC @ 16ºC 3355 5184 4699 6925 4582 6769 5000 max Bending Beam Rheometer Creep Stiffness @ -18ºC, MPa @ -24ºC, MPa Slope, m-value @ -18ºC, MPa @ -24ºC, MPa 227.0 505.5 0.323 0.261 266.0 455.0 0.298 0.242 259.0 517.0 0.295 0.246 300 max 0.300 min (BBR Basis)59.1 – 30.160.1 – 27.860.3 – 27.4 Penetration @ 25ºC, 100g, 5 sec12367 HMA was not the same base AC as the WMA
Rte 135 Evotherm 58-28 3G St. Isidore Construction
Location of Evotherm 3G Job on Rte 135 Job: - Pulv. + Gran + Dbl Chip + D Mix - 3km WMA-D - 1km HMA D St. Isidores Plant ~24 km haul
Rte 135: NBDOT Surface Mix Designs BlendType D MixHMAWMA 12.5 mm Stone32.9 6.3 mm Fine42.242.3 6.3 mm Washed Fine11.3 Blend Sand7.5 PG 58-286.1 PG 58-28 – 3G Evotherm®6.0 Physical Properties Mixing Temperature °C150125-130 Compaction Temperature °C135-140120 N design – Gyrations100 Bulk Relative Density2.5032.469 Maximum Relative Density2.6032.574 % Air Voids3.844.07 % VMA15.4616.48 % VFA75.275.3 Tensile Strength Ratio (with anti-strip)83.2 w AS89.3 wo AS AC lowered to maintain voids HMA required antistrip and WMA did not!!!
Rte 135: Surface Mixes NBDOT Test Data Mix TypeHot MixWarm Mix SampleJMF1123 Time9:45 am10:10 am1:15 pm7:40 am DateSept 25Sept 26Sept 30Oct 1 Sieve 16.0 mm100.0 12.5 mm100.0 99.4100.0 9.5 mm94.393.693.196.393.9 6.3 mm73.177.373.376.673.6 4.75 mm62.367.961.765.163.0 2.36 mm39.944.939.942.041.2 1.18 mm26.630.227.128.027.7 0.600 mm18.820.118.618.818.6 0.300 mm11.711.811.411.711.4 0.150 mm7.66.8 7.36.7 0.075 mm5.04.44.65.14.3 HotWarm % Asphalt Cement6.16.06.386.116.266.14 Bulk Recompacted Density2.5032.4692.4552.4982.4812.486 Maximum Theoretical Density2.6032.5742.5462.5762.5624.569 % Air Voids3.844.073.573.033.163.23 % VMA15.4616.4817.3215.616.3116.03 % VFA75.275.379.480.6 79.8 WMA and HMA results are both very consistent with JMF
Energy Savings- St Isidore Rte 135, 2008 Black Line – HMA Agg Temp = 160C Tracer for WMA Agg Temp = 125C Burner Position: - HMA typically at 2.5. - WMA was at 1.6 - ~ 36% if dir. propl 4000 lb batch; baghouse Plant fired with propane
NB – St Isidore (3G) Pulverize then Double Chip
Evotherm-3G Rte 135 (contd) Density: –HMA density= 93.2% –WMA density= 94%, 92.4% –Needed to keep breakdown roller close to paver in cool weather.
Field Observations & Comments Significant decrease in fumes at HMA plant & job site. –Reason: Light oils boil off @ ~ 285F/140C –Employees were very pleased Much cooler and safer working environment Less end of load segregation Cleaner truck boxes: –Mix did not stick to box and flowed smoothly to the paver.
Field Observations & Comments (contd) WMA maintained temperature and stayed workable longer. Easy to get density with WMA. WMA is a more forgiving mix; especially if waiting for trucks. RTR used soap / additive to prevent pick-up; no significant issues. Longitudinal joints were very tight and look great -Tighter jt. = less infiltration, less freeze thaw, less oxidizing, less ravelling, less cold joint cracking.
WMA very stable with no apparent tender zone Good roller support & no shoving at unconfined edge. Field Observations & Comments (contd) Modern Rte 106
In 2009 H2O was added to aggregate conveyor to enable mix temperature reduction in the batch plant; Reason: Freshly crushed aggregate. Field Observations & Comments (contd)
Evotherm WMA in Canada 2009 90,000 MT (18 projects): –1 in BC (500MT) –1 in Saskatchewan (600MT) –1 in Manitoba (7000MT) –4 in Ontario (13700MT) –1 in Quebec (5500MT) –1 in NS (2000MT) –9 in NB, (6 Evotherm-3G/DAT, 3 HyperTherm); NB did ~60,000MT of WMA!! (~8% of NBDOT program)
Review of NB Projects (contd) NBDOT Patching Crew; 2009 WMA
Conclusions WMA and HMA performed equally well in both the field and the lab. Handling/placing of WMA and HMA was identical in the field. Evotherm received positive feedback from contractors. WMA has potential to have a large role in the future of paving. WMA appears to produce better longitudinal joints that that could be less prone to raveling and cold joint cracking. Depending on the project WMA can save you money/ tonne relative to HMA.