ENHANCING STRENGTH AND DURABILITY OF CONCRETE USING RESIDUALS AND - PowerPoint PPT Presentation

ENHANCING STRENGTH AND DURABILITY OF CONCRETE USING RESIDUALS AND REJECT FIBERS FROM PULP AND PAPER MILLS by Tarun R. Naik Presented at the Workshop and Construction Demonstration for Use of Residuals and Reject Fibers from Pulp and Paper Industry in Concrete and CLSM Brookfield and New Berlin, WI, August 28, 2008 Center for By-Products Utilization

Micro-fibers from Pulp and Paper Mill Wastewater Treatment Residuals • Solid residue removed from mill wastewater before the water is discharged or reused. • Removed via a two-step (gravity/primary and biological/secondary). • Usually, dewatered before disposal or beneficial use. Center for By-Products Utilization

Mill Clarified Wastewater Primary Secondary Water Clarifier Clarifier Primary Secondary Residual Residual Dewatering Dewatered Residual Recovered Water Paper Mill Wastewater Treatment Process Center for By-Products Utilization

Pulp and Paper Mill Residual Solids in Concrete • Approximately 60 % of the residual solids generated in the USA is either landfilled or burned. • Because of cellulose fibers in the residual solids, the residual solids could become an economical source of fibers for use in concrete. Center for By-Products Utilization

Scanning electron micrograph of Residual S Center for By-Products Utilization

700 600 500 S t eel 400 C arbon 300 W ood C el l ul ose 200 100 0 A spect R at i o, T ensi l e S t rengt h M odul us of L / D (M P a) E l ast i ci t y (G P a) Properties of Micro-fibers Center for By-Products Utilization

Pulp and Paper Mill Residual Solids in Concrete • There have been very few investigations. • Best performance of concrete seems to be achieved if the residual solids were collected prior to chemical conditioning and solidification. Center for By-Products Utilization

As-received fibrous residual C1 Center for By-Products Utilization

CONCRETE PROJECT 1 Center for By-Products Utilization

Characterization of the Residuals Seven sources of residual solids from various types of mills were selected. – Primary and/or combined (primary + secondary) residuals – Virgin-fiber and recycled-fiber residuals • Physical and chemical properties determined. • Effects of dispersants on sludge to separate fibers established. Center for By-Products Utilization

Characteristics of Residuals Type of Residual 6 Primary, 1 Fiber reclaim Fiber Origin 5 Virgin, 1 Recycled, 1 Mixed Moisture Content (%)* 153 (84-230) Wood Fiber (%)* 57 (35-94) LOI at 590 ° C (%)* 65.9 (43.6-99.6) Specific Gravity 1.83 (1.56-2.17) Avg. Fiber Length, L L (mm) 1.27 (0.85-1.68) * % of oven-dry mass. Center for By-Products Utilization

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Strength and Durability of Concrete Containing Residual Fibers Mixture Proportions – Residual content of 0.65 to 1.5%. – Initial and final setting times evaluated. – Air-entraining admixture (AEA) was not used. – HRWRA was used to adjust slump. Center for By-Products Utilization

Mixture Proportions (per m 3 ) and Fresh Properties Mixture Ref1 C1 C2 WG WV Ref2 BR I S Residuals (kg) 0 15.6 15.7 15.6 15.7 0 8.5 16.0 15.7 HRWRA (L) 0.8 1.8 3.0 2.2 3.4 0.8 1.5 3.5 5.5 Cement (kg) 368 360 363 359 361 367 365 368 363 Sand (kg) 856 837 848 836 841 852 847 855 841 19-mm Coarse 1050 1030 1030 1020 1030 1050 1040 1050 1030 Aggregate (kg) W/Cm 0.43 0.41 0.43 0.45 0.44 0.43 0.41 0.42 0.44 Slump (mm) 115 90 150 180 125 75 125 90 75 Air Content 1.6 2.8 1.6 1.8 1.7 1.9 2.3 1.3 1.8 (%) Unit Wt. 2430 2390 2420 2400 2410 2420 2410 2440 2410 (kg/m 3 ) Center for By-Products Utilization

60 (M P a) 50 R ef . 1 Strength 40 C 1 30 C 2 ve W G 20 C om pressi W V 10 0 0 20 40 60 80 100 A ge (days) Compressive strength of concrete (ASTM C 39) Center for By-Products Utilization

60 (M P a) 50 S tren gth R ef. 2 40 B R 30 I ve 20 S C om p ressi 10 0 0 20 40 60 80 100 A ge (days) Compressive strength of concrete (ASTM C 39) (cont’d) Center for By-Products Utilization

0. 02 0. 01 (% ) 0. 00 R ef. 2 C hange -0. 01 0 50 100 150 200 250 B R -0. 02 I L ength -0. 03 S -0. 04 -0. 05 -0. 06 A ge (days) Length change of concrete due to curing in water and drying in air Center for By-Products Utilization

Resistance of Concrete to De-icing Chemicals (ASTM C 672) 6 5 4 Scaling Rating R BR 3 I S 2 1 0 0 10 20 30 40 50 60 70 Salt Scaling Cycle Center for By-Products Utilization

Change in Dynamic Modulus of Elasticity of Concrete Due to Freezing and Thawing (ASTM C 666 A) Relative Dynamic Modulus of Elasticity (%) 100 80 R BR 60 I S 40 20 0 0 50 100 150 200 250 300 350 Freezing and Thawing Cycle Center for By-Products Utilization

Residual Flexural Strength (ASTM C 1339) • Concrete containing residuals showed slightly improved residual-strength than concrete without residuals. Center for By-Products Utilization

Charge Passed (Coulombs) 6000 5000 High 4000 Moderate 3000 2000 Very Low 1000 Negligible 0 Ref. C1 C2 WG WV Ref. BR I S 1 2 Mixture Name Electrical Indication of Chloride Ion Penetrability Into Concrete (ASTM C 1202) Center for By-Products Utilization

Abrasion test Center for By-Products Utilization

nutes 3. 0 M i 2. 5 (g) x on 2. 0 S i A fter A brasi 1. 5 L oss 1. 0 of 0. 5 M ass 0. 0 R ef. 1 C 1 C 2 W G W V R ef. 2 B R I S M i xture N am e Mass loss of concrete due to abrasion Center for By-Products Utilization

Construction Demonstration (2004) Center for By-Products Utilization

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CONCLUSIONS When compared to a reference concrete containing no residuals, concrete containing residuals exhibited: • Slightly lower compressive strength • higher average residual-strength • Equivalent drying-shrinkage • Improved resistance to freezing and thawing • Equivalent or lower chloride-ion penetration resistance and abrasion resistance. Center for By-Products Utilization

CONCRETE PROJECT 2 (for WI-DNR) Center for By-Products Utilization

Mixture Proportions and Fresh Properties of Prototype Concrete Mixtures - Project 2 Mixture Designation 1 2 3 4 5 Fibrous Residual Source (None) BR BR C1 C1 Cement (lb/yd 3 ), C 563 593 575 519 522 Class C Fly Ash (lb/yd 3 ) 95 93 102 88 94 Fine Aggregate, SSD (lb/yd 3 ) 1340 1355 1340 1255 1235 Coarse Aggregate (3/4-in. max.), 1695 1715 1715 1615 1565 SSD (lb/yd 3 ) Fibrous Residual, as-received 0 14 20 24 38 (lb/yd 3 ), FR Water (lb/yd 3 ), W 275 282 275 236 286 Air Entraining Admixture (oz/yd 3 ) 5 0 0 0 0 W/C 0.42 0.41 0.41 0.39 0.46 Slump (in.) 3-1/4 3-3/4 3 3-3/4 4-1/2 Air Content (%) 5.8 2.2 2.6 9.2 9.3 Density (lb/ft 3 ) 147.0 150.3 149.2 138.5 138.6 Center for By-Products Utilization

8000 50 7000 Compressive Strength 6000 40 1 5000 2 30 (MPa) (psi) 3 4000 4 3000 20 5 2000 10 1000 0 0 1 10 100 1000 Age (days) Compressive Strength of Prototype Concrete – Project 2 Center for By-Products Utilization

700 Splitting Tensile Strength 600 4 500 1 3 2 400 (MPa) (psi) 3 300 2 4 5 200 1 100 0 0 0 20 40 60 80 100 Age (days) Splitting Tensile Strength of Prototype Concrete – Project 2 Center for By-Products Utilization

100 Relative Dynamic Modulus of 90 1 80 Elasticity (%) 2 70 3 4 60 5 50 40 0 30 60 90 120 150 180 210 240 270 300 Freezing and Thawing Cycles Resistance of Prototype Concrete to Cycles of Freezing and Thawing – Project 2 Center for By-Products Utilization

• When tested for resistance to freezing and thawing, concrete made with wood fibers showed generally similar performance as air-entrained concrete made without fibers. Center for By-Products Utilization

CONCRETE PROJECT 3 Using High-Carbon Materials Center for By-Products Utilization

Background and Objectives • This testing work was conducted to evaluate the use of high-carbon fly ash and carbon in non-air entrained concrete. • Fibrous residual from pulp and paper mill was used to improve the durability of the concrete to freezing and thawing. Center for By-Products Utilization

Background and Objectives (cont’d) • This new technology would also lead to reduced amount of high-carbon fly ash and pulp mill residual solids going to landfills. • It is believed that the improvement in concrete durability can be achieved without depending on specialty chemical air-entraining admixture, even when high-carbon fly ash is used in such concrete mixtures. Center for By-Products Utilization

MIXTURES – Group 1 • Fibrous residual contents: Approximately 0.25, 0.5, and 0.75% by mass of concrete. • Presque Isle activated carbon: 25% of the sum of cement and Presque Isle activated carbon. • Valley high-carbon fly ash: 14% of the sum of cement and Valley high-carbon fly ash. • Tests: Compressive strength, flexural strength, chloride-ion penetrability, and resistance to freezing and thawing. Center for By-Products Utilization