Silent surfaces: an experience in Portugal Elisabete Freitas Elisabete Freitas & Paulo Pereira & Paulo Pereira • • Universidade do Minho, Portugal • Universidade do Minho, Portugal • Joel Paulo & Paulo & Bento Bento Coelho Coelho • Joel • I nstituto Superior Té écnico, Lisbon, Portugal cnico, Lisbon, Portugal • I nstituto Superior T • Presented by by • Presented • Fabienne Anfosso Anfosso- - L Lé éd dé ée e, , LCPC, France LCPC, France Fabienne • • fabienne.anfosso@lcpc.fr • Portorož, Slovenia
Organization o Overview of past Portuguese experiments o Experiment description • Properties of asphalt mixes • Noise measurement • Weather, Texture, Skid resistance o Results • Noise – far field test • Noise – near field test • Noise – far field versus near field test • Noise – near field test – spectra o Conclusions Portorož, Slovenia
Overview of past Portuguese experim ents o Studies based on environm ental noise - Leq ( 1 5 -3 0 m in) • Gap graded asphalt rubber versus “rough” dense asphalt noise reduction = 5 to 8 dB( A) • Gap graded asphalt rubber versus cement concrete noise reduction = 8 to 1 0 dB( A) Portorož, Slovenia
Overview of past Portuguese experim ents o Studies based on Controlled Pass-By Method ( CPB) • Porous asphalt versus dense asphalt and dry versus wet surfaces Ref. speed PAw - PAd DAw - DAd DAd - PAd DAw - PAw (km/h) Vehicle (dB(A)) (dB(A)) (dB(A)) (dB(A)) L1 80 1.4 6.1 7.6 2.9 L2a 70 0.3 0.5 3.3 2.5 L2b 70 2.0 1.0 3.8 2.8 L1 110 2.5 6.2 7.3 3.6 L2a 85 3.2 4.9 1.3 0.0 L2b 85 2.6 2.2 0.5 0.1 Portorož, Slovenia
Overview of past Portuguese experim ents o Studies based on Controlled Pass-By Method ( CPB) • Layers assessed: gap graded asphalt rubber, dense asphalt, unconventional gap graded asphalt mixtures with small aggregate size (< 7 mm) 5.7 6 5.4 4.1 4 Variation of the average noise level (dB(A)) 3.4 3.3 2.9 2.3 1.9 2 1.6 1.6 1.6 1.5 1.5 1.3 0.3 0.1 0 50 70 90 50 70 50 70 90 -1.2 -1.3 -1.4 -2 Light vehicle (P) Heavy vehicle Light vehicle (S) -2.4 -2.8 -2.8 -3.0 -3.3 -3.4 -3.4 -3.5 -4 -3.7 -3.7 -4.1 -4.6 -4.6 -4.7 -4.8 -5.3 -5.4 -6 -5.7 -5.8 -6.1 -6.9 -7.3 -8 -7.7 Speed level (km/h) S2(GG6) S5(GG7) S7(GGAR10) S1(GG12) S6(GGAR12) S3(GGAR14) Portorož, Slovenia
Overview of past Portuguese experim ents o Analysis • The big maximum aggregate size of conventional Portuguese surface mixtures seems to control noise 100 DA 0/16 90 PA 0/16 Percentage passing (%) 80 TL 0/12 (rough 1) 70 TL 0/19 (rough 2) 60 TL 0/10 (smooth) 50 TL 0/8 (France) 40 RA 0/19 (rough) 30 GGAR 20 10 0 0.01 0.1 1 10 100 Sieve size (mm) Portorož, Slovenia
Experim ent description o Rehabilitation project: urban distribution road in the centre of the city of Braga o Three surface layers constructed consecutively: • one dense asphalt layer with 12 mm of maximum aggregate size • two very-thin surfaces with different grading (adaptation of the very-thin layers, widely used in France, to Portuguese conditions) o Noise assessment methods • Controlled Pass-By method • Close Proximity Method o Other complementary tests • Macrotexture and skid resistance Portorož, Slovenia
PK 2+743m PK 0+000m N DA2 (0/12) TL2 Properties of asphalt m ixes PK Max. 0+550m Type of Thickness Void content* aggregate mix (cm) (%) size (mm) TL1 3 8 15.0 PK 1+790m TL2 3 8 18.5 DA1 (0/12) DA 4 12 4.9 TL1 (0/12) PK 1+770m PK 1+885m 100 PK 0+950m 90 TL2 PK 0+860m DA 0/12 80 PK Percentage passing (%) TL1 0+640m 70 60 (DA1 0/12) 50 DA2 (0/12) 40 30 20 PK TL2 2+743m TL1 10 DA 0 Microphone PK position 0.01 0.1 1 10 100 0+000m Sieve size (mm) Portorož, Slovenia
Testing vehicles and speed o 2 passenger cars • 2 pass-bys each at 50, 80, 110 km/ h o 1 tri-axle truck: • 2 pass-bys at 60, 80, 90 km/ h Portorož, Slovenia
Noise m easurem ent o CPX method • Based on ISO CD 11819-2 • Captured signals in a dedicated audio module – Matlab • Test sections with more than 100 m Portorož, Slovenia
Noise m easurem ent o CPB method • Based on ISO 11819-1 (1.2 m, 7.5 m) • Simultaneous measurement in each direction (2 microphones, 2 surface layers) • Tests carried out at night • Traffic closed in both directions • Vehicle’s engine switched on Portorož, Slovenia
W eather / Texture / Skid resistance o Air temperature ≈ surface temperature: [ 5.5; 7.9] º C o Wind speed: < 1 m/ s o Texture near microphone position: • TL 1 ≈ 1.1 mm • TL 2 ≈ 1.3 mm • DA1 ≈ 0.8 mm • DA2 ≈ 0.6 mm o Skid resistance: 0.6 (average) Portorož, Slovenia
Noise – far field test o Heavy vehicle 95 1 st TL1 90 3 rd DA1 Lmax (dB(A)) 85 DA2 4 th 80 2 nd TL2 75 40 50 60 70 80 90 100 110 120 Speed (km/h) Portorož, Slovenia
Noise – far field test o Light vehicles 85 2 nd TL1 80 DA1 3 rd 75 Lmax (dB(A)) 70 DA2 4 th 65 TL2 1 st 60 40 50 60 70 80 90 100 110 120 Speed (km/h) Portorož, Slovenia
Noise – far field test o Noise level at reference speed Speed Noise level (dB(A)) Type of vehicle (km/h) TL1 DA1 DA2 TL2 Max-Min 60 83.1 82.2 82.8 81.6 1.6 Heavy 80 88.9 88.6 87.1 85.9 2.9 90 91.2 91.2 88.8 87.7 3.5 50 65.5 67.0 67.7 63.8 3.9 Light 80 69.5 73.4 74.1 68.5 5.6 110 72.2 77.8 78.5 71.7 6.8 Portorož, Slovenia
Noise – far field test o Comparison - TL2 with GG asphalt rubber (10 mm) and DA Speed Noise level (dB(A)) Type of vehicle DA GGAR (km/h) DA (0/16) –TL2 GGAR (0/10) – TL2 (0/16) (0/10) 50 71.2 66.5 7.4 2.7 Light 80 77.7 71.0 9.2 2.5 110 82.1 74.1 10.4 2.4 Portorož, Slovenia
Noise – near field test o CPX vehicle 100 TL1 95 DA1 Lmax (dB(A)) 90 DA2 85 TL2 80 40 50 60 70 80 90 100 110 120 Speed (km/h) Portorož, Slovenia
Noise – near field test o Noise level at reference speed Speed Noise level (dB(A)) (km/h) TL1 DA1 DA2 TL2 Max-Min 50 81.0 83.8 82.7 80.9 2.9 80 87.4 90.5 90.0 87.1 3.1 110 91.8 95.0 95.0 91.3 3.3 Portorož, Slovenia
Noise – far field versus near field test o Noise level at reference speed 100 TL1 95 TL2 90 Lmax - CPX (dB(A)) DA1 85 DA2 80 Linear (TL1) 75 Linear (TL2) 70 Linear (DA1) 65 Linear (DA2) 60 60 65 70 75 80 Lmax - SPB (dB(A)) Portorož, Slovenia
Noise – far field versus near field test o Noise attenuation 22.0 20.0 Noise attenuation (dB(A)) TL1 18.0 DA1 16.0 DA2 TL2 14.0 12.0 10.0 40 50 60 70 80 90 100 110 120 Speed (km/h) Portorož, Slovenia
Noise – near field test – noise spectra o Example spectra at 80 km/ h Cancelling effect 90,0 80 Km/h on thin layers: 85,0 80,0 after device 75,0 verification, further TL1 tests have shown 70,0 ) A B TL2 d similar trend ( DA1 x a 65,0 m DA2 A L 60,0 55,0 50,0 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 1/3 Octave Bands (Hz) Portorož, Slovenia
Conclusions o Silent surfaces need more attention in Portugal o With the use of the adapted thin layers important noise reductions can be achieved (up to 7 dB(A)) o Based on this experience, the thin layers studied may be recommended to be used in all types of roads (rural and urban) o It is inttended to repeat noise tests every year Portorož, Slovenia
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