Utilizing Repeated Load Triaxial Testing in the Assessment of Local Materials on Taihape Napier Road Seal Extension

133 km Taihape to Napier 37km unsealed Alternatives 291km and 275km Strategic Increased usage if sealed Potentially State Highway 21km in Rangitikei District

56 km NE from Taihape Mangaohane Rd to Gentle Annie

Four sections Existing alignment Minor safety improvements

Rotten rock Rock > R2 Varying subgrades Pumice, ash Clay, sand

Design Life 25 years AUSTROADS

Local rock subbase

Local river resourced basecourse

Fragile network 15 000 cu m M4 AP40 basecourse 70km cartage potential $500 000 per year maintenance

Pavement Rutting design to avoid

Rutting shear in subgrade Aggregate Soil Austroads Pavement Design Guide ensures adequate cover/protection to subgrade

Rutting bshear in base Rutting compaction in base b b/3 Aggregate Soil Aggregate Soil Specifications usually ensure aggregates do not fail (but not always! Especially if they get wet) A Repeated Load Triaxial Test (applies 350,000 load cycles): - Will determine the amount of rutting in the aggregate (wet and dry) - To determine suitability of chosen materials

Repeated Load Triaxial Testing

Repeated Load Triaxial Testing Soaking sample For saturated test

Material Sampling Local Aggregate

Repeated Load Triaxial Testing Compaction Local Aggregate After test

Repeated Load Triaxial Test Results - DRY 2 Typical Results for TNZ M4 Basecourse Aggregates - Dry/Drained 1.8 Permanent strain [%] 1.6 1.4 1.2 1 0.8 21 Local Agg - M4 middle grading Tests 3 & 5 average TNZ M4 basecourse Test 1 very good TNZ M4 Test 7 Poor TNZ M4 Test 21 Local aggregate Taihape/Napier 7 21 5 0.6 0.4 3 0.2 1 0 0 50000 100000 150000 200000 250000 300000 Number of load cycles [-]

Permanent strain [%] 2 1.8 1.6 1.4 1.2 1 0.8 0.6 Repeated Load Triaxial Test Results - WET Typical Results for TNZ M4 Basecourse Aggregates - Saturated/Undrained 22 Taihape/Napier local agg - M4 middle grading (saturated) - 22 8 4 6 2 Tests 4 & 6 avg M4 Test 2 v. good M4 Test 8 Poor TNZ M4 Test 22 Local aggregate Taihape/Napier (Note : very sensitive to Water) 0.4 0.2 0 0 50000 100000 150000 200000 250000 300000 Number of load cycles [-]

30 25 20 15 10 5 0 Traffic Loading Limit - RLT Test Dry/drained Analysis of RLT Results Rutting Dry 3. V. Good - TNZ M4-95%MDD - Dry 5. Avg. TNZ M4 - Dry 7. V. Poor TNZ M4 - Dry 21. Taihape/Napier - middle - 95%MDD - Dry Material Traffic Loading Limit (Million ESAs

2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 Traffic Loading Limit - RLT Test Saturated/Undrained Not suitable as a basecourse as failed in stage 6 Analysis of RLT Results Rutting Wet 2. V. Good - TNZ M4-101%MDD - Saturated 6. Avg. TNZ M4 - Saturated 8. V. Poor TNZ M4 - Saturated 22. Taihape/Napier - middle - 95%MDD - Saturated Material Traffic Loading Limit (Million ESAs

Repeated Load Triaxial Test Results WET Stabilised Local Aggregate Combinations Test # Source Agg. % Subgrade soil % Hydrated Lime % Cement 24 Taihape/Napier local agg. 33% 2% - 25 Taihape/Napier local agg. - 2% - 26 Taihape/Napier local agg. - 2% 1% 27 Taihape/Napier local agg. - - 1.5%

Repeated Load Triaxial Test Results - WET Taihape/ Napier Stabilised Aggregates - Saturated/Undrained Permanent strain [%] 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 24 - Taihape - Agg. + 33% Soil + 2% Lime 25 - Taih. Agg. + 2% Lime 26 -Taih. Agg. + 2% Lime + 1% Cement 27 - Taih. Agg. + 1.5% Cement 10 - Fine M4 + 2% Cement 12 - Coarse M4 + 2% Cement 14 - GAP40 + 2% Cement 0 50000 100000 150000 200000 250000 300000 350000 Number of load cycles [-] 12 14 24 10 27 25 26

100 90 80 70 60 50 40 30 20 10 0 Traffic Loading Limit - RLT Test Saturated/Undrained Not suitable as a basecourse as failed in stage 7 Analysis of RLT Results Rutting Wet 10. Fine TNZ M4 + 2% Cement 12. Coarse TNZ M4 + 2% Cement 14. GAP40 + 2% Cement 24. Taihape Agg. + 1/3rd Soil + 2% Lime 25. Taihape Agg. + 2% Lime 26. Taihape Agg. + 2% Lime + 1% Cement 27. Taihape Agg. 1.5% Cement Material Traffic Loading Limit (Million ESAs)

Durability water for 1 month Agg + 1/3 rd soil + 2% Lime Agg + 2% Lime + 1% Cement Agg + 2% Lime Agg + 1.5% Cement Local Aggregate + 2% Lime Best (lowest cost and performs well in tests)

Pavement Design Surfacing Basecourse Insitu 2% lime + local agg. 100 mm Basecourse Consider using 2% Lime and 1% Cement mixture Upper Sub-base Insitu 2% lime +local agg. Lower Sub-base Local aggregate (unmodified) 100 mm 150 mm Upper Sub-base 100mm is sufficient depth to protect underlying layers as any deeper compaction is poor and no cementation Lower Sub-base leave unmodified as there is poor compaction this close to subgrade and no cementation occurs Natural existing subgrade Assumed CBR=5%

Spread and crush raw material 150mm sub-base 150mm basecourse Raw materials identical

Stabilise 200mm 2% Lime 7% moisture content, modified

Reduced maintenance on local network Minimised resource consent costs for materials

Client savings $ 1 000 000 Efficiencies in construction Innovation, science, practical