Lightweight aggregates in Civil Engineering applications Arnstein Watn Senior Scientist, SINTEF
SINTEF Independent Multiscience Research Institute About 1800 employees Closely linked to the Universities -Norwegian University of Science and Tecnology (NTNU, Trondheim) -University of Oslo Technology for a better Society SINTEF on the Web: http://www.sintef.no/ 2-2002-06-14
PRESENTATION CONTENT Material properties and test methods Applications and structural solutions Construction Quality control 3-2002-06-14
R&D project Physical properties Thermal properties Mechanical properties Durability Structural performance 4-2002-06-14
Laboratory tests-results DENSITY (kg/m 3 ) Material Loose Compacted Dry 25% water 0-32 335 370 (10%) 460 4-20 295 330 (11.8%) 410 10-20 280 310 (10.7%) 390 5-2002-06-14
2500 2000 Density (kg/m3) 1500 1000 500 0 Leca 10-20 Leca 0-32 water crushed rock Materials 6-2002-06-14
Thermal properties 0.22 Thermal conductivity, W/mK 0.20 0.18 0.16 0.14 0.12 0.10 0 5 10 15 20 25 Water content (volumetric) % 7-2002-06-14
Large scale oedometer test Leca 4-20 Leca 10-20 Leca 0-32 40 Oedometermodulus, M, (MPa) 30 20 10 0 0 100 200 300 400 500 600 Vertical stress (kpa) 8-2002-06-14
Effect of compaction 9-2002-06-14
Triaxial tests-friction properties Failure angle tan b = 1.02 b = 45 Characteristic friction tan k = 0.85 k = 41 Attraction/(cohesion) a (c u ) = 0 (0) kpa 10-2002-06-14
Resistance against permanent deformations Failure zone a Failure line Rearrangement of particles Elasto-plastic zone c Pure elastic zone elastic Elastic limit line Crushing of particles 11-2002-06-14
Cyclic triaxial tests Leca 10-20 Leca 0-32 Resilient - modulus (MPa) 600 500 400 300 200 100 0 0 50 100 150 200 Mean stress (kpa) 12-2002-06-14
Mechanical properties-summary Strength and stiffness properties comparable to conventional materials (gravel/crushed rock) Provided the stress level is not resulting in crushing of the grains 13-2002-06-14
Field investigations-existing fills 14-2002-06-14
Field Investigations Existing fill with age up to 8 years No crushing from traffic observed Some damage/crushing of surface particles from compaction Water content, w= 15-40% (note weight %) 15-2002-06-14
Large scale model test 150 cm 150 cm loadplate hydraulic actuator Load cell Asphalt Crushed rock geotextile Designed for AADT = 5 000 30, 40 and 50 kn load 5 Hz loading frequency Leca 10-20 mm geotextile XPS Measured stresses and strains in the Leca layer 190 cm 16-2002-06-14
Model testpermanent deformations Deformation, mm. 25 20 15 10 5 0 Top Leca layer Top asphalt 0 1,000,000 2,000,000 3,000,000 4,000,000 5,000,000 Number of load pulses 17-2002-06-14
Numerical analyses Vertikale spenninger (kpa) -11.9-11.0-10.1-9.20-8.31-7.41-6.51-5.62-4.72-3.83-2.93-2.04-1.14-2.46 18-2002-06-14
Field test, Sandmoen 19-2002-06-14
Field test-lay out 20-2002-06-14
Field test-wedge section 21-2002-06-14
Plate load tests 22-2002-06-14
Field test-plate load test Location E1 E2 E2/E1 Instrumented part Wedge part Strong end Wedge part Weak end 110,2 205,4 1,86 83,1 160,2 1,92 63,5 181,7 2,86 23-2002-06-14
Bearing capacity FWD Distance from asphalt edge [m] 3.5 3 2.5 2 1.5 1 0.5 0 Section 3 Section 4 6.2 6.4 4.9 4.4 9 10 10 10 9.6 10 9.9 9.8 10.1 10.1 10.2 10.5 9.8 8.9 8.5 8.1 7.8 8.1 8.4 7.9 8.4 6.8 6.6 6.3 6.3 6.5 6.6 6.1 7.1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [m] 24-2002-06-14
Field test - Instrumented load test 25-2002-06-14
Vertical stress measurements D e p t h [m] 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Vertical Stress [kpa] 0 100 200 300 400 500 600 700 800 10 cm asphalt 30 cm crushed rock 40 cm Leca 0.8 Edge (0.15m) Inner track (3 m) (distance from asphalt edge) 26-2002-06-14
Field test-rutting 35 30 Section 1 Section 2 Section 3 Section 4 Rut depth [mm] 25 20 15 10 5 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 Current distance [m] 1999-06-24 inner track 1999-06-24 outer track 1999-08-04 inner track 1999-08-04 outer track 27-2002-06-14
Field test- Temperature 15 Measured temperatures in road with Leca. Daily mean value 10 Asphalt surface Temperature, ('C) 5 0-5 -10 2 cm below surface Between asphalt layers Bottom of asphalt Top crushed rock Top LECA Middle of LECA Bottom of LECA Top sand layer Bottom of sand layer -15-20 20 cm depth in subsoil Air temperature 2m above ground -25 99.11.06 99.11.16 99.11.26 99.12.06 99.12.16 99.12.26 00.01.05 Date 28-2002-06-14
CONCLUSIONS Physical properties: Unit weight (compacted drained): 4-5 kn/m 3 Compaction: 10-12 % Mechanical stiffness and strength: Comparable to conventional material (stress level blow crushing level) 29-2002-06-14
Conclusions Structural performance Suitable as frost insulation layer Suitable as light weight fill material Suitable as part of lower bearing layer 30-2002-06-14
Bearing capacity during thawing 31-2002-06-14
Road surface cracking 32-2002-06-14
Insulation effect 33-2002-06-14
Structural solution 4cm Agb 6 cm Ag 20 cm Fk 30 cm LWA Existing frost susceptible road Separating geotextile 34-2002-06-14
Bearing capacity-paradise 35-2002-06-14
Required insulation thickness Nødvendig tykkelse av isolasjonslag Nødvendig isolasjonstykkelse (cm) 80 60 40 20 0 0 10000 20000 30000 40000 Frostmengde (timegrader) 1 2 3 4 36-2002-06-14
Bearing capacity No c ounte r fill Shear surface 37-2002-06-14
Light weight fill road embankment 38-2002-06-14
Road and railway extension Railway 39-2002-06-14
Road extension 40-2002-06-14
Settlements 41-2002-06-14
Bridge abutment We d g e Pile s 42-2002-06-14
Bridge abutments-visible settlements 43-2002-06-14
Bridge abutment 44-2002-06-14
Slope stabilisation Wa te r She ar surfac e 45-2002-06-14
Slope stability improvement 46-2002-06-14
Insulation of drainage ditch 47-2002-06-14
QUALITY REQUIREMENTS Internordic working group : Nordtest Method planned implemented into a European Standard Required material properties and test methods Quality requirements on construction and field control Final version planned by April 2001 48-2002-06-14
Required material properties Density Grain size (variation) Amount of crushed particles Water content Thermal conductivity Water adsorption Compressive stiffness Compressive strength Dynamic compression Dynamic E-modulus Environmental acceptability 49-2002-06-14
Installation 50-2002-06-14
Installation by blowing 51-2002-06-14
Installation and compaction 52-2002-06-14
Quality control-field Detailed execution guidelines Layer thickness Compaction equipment and method Number of passages Overburden compaction 53-2002-06-14
Quality control-field Functional requirements Degree of compaction methods proved to be suitable are not available Bearing capacity Plate bearing tests, light falling weight and Dynamic Cone Penetrometer (DCP) Integrity of aggregates Counting of damaged and crushed aggregates 54-2002-06-14
Plate load test 55-2002-06-14
Properties - light - high stiffness and strength LWA in Civil Engineering Applications - reduce settlements (differential and total) - increase stability (embankments, slopes) - reduce earth pressure - frost insulation Quality - required material properties - installation and compaction - field control 56-2002-06-14
LWA for Civil Engineering Properties - application - control Leca 10-20 Leca 0-32 R es ilient - m odulus (M Pa) 600 500 400 300 200 100 0 0 50 100 150 200 Mean stress (kpa) 57-2002-06-14