Center for By-Products Utilization

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1 Center for By-Products Utilization DEVELOPMENT OF CLSM USING COAL ASH AND WOOD ASH, A SOURCE OF NEW POZZOLANIC MATERIALS By Tarun R. Naik, Rudolph N. Kraus, Shiw S. Singh, and Parisha P. Chanodia Report No. CBU REP-420 January 2001 To be submitted to the ACI Materials Journal. Department of Civil Engineering and Mechanics College of Engineering and Applied Science THE UNIVERSITY OF WISCONSIN - MILWAUKEE

2 CLSM CONTAINING MIXTURES OF COAL ASH AND A NEW POZZOLANIC MATERIAL Tarun R. Naik, Rudolph N. Kraus, Shiw S. Singh, Parisha P. Chanodia ABSTRACT Significant amount of ash is generated from burning wood with supplementary fuels such as coal, oil, natural gas, and coke by pulp and paper mills and wood-products manufacturers. Thus, the ash generated from such facilities is a mixture of wood ash and other ashes generated from such supplemental fuels. In this investigation, such wood ash is referred to as a combined-fuel ash (CFA). This investigation was carried out to develop Controlled Low-Strength Materials (CLSM) mixtures using various sources of CFAs. Three different series of CLSM mixtures were manufactured using five sources of CFAs. Each series of CLSM mixtures was designed for a different long-term compressive strength, <0.7 MPa (<100 psi), 0.7 to 3.4 MPa (100 to 500 psi), and 3.4 to 8.3 MPa (500 to 1,200 psi). All CLSM mixtures were tested for flow, bleedwater, settlement, shrinkage and cracking, setting characteristics, density, compressive strength, and permeability. The results revealed that CLSM, meeting ACI 229 requirements, can be manufactured using substantial amounts of CFAs. Key words: controlled low-strength materials; flowable fill; CLSM; backfill; wood ash; combined fuel ash; flowable matter 1

3 Prof. Tarun R. Naik is Director of the UWM Center for By-Products Utilization, Department of Civil Engineering and Mechanics at the University of Wisconsin-Milwaukee. He is a member of ACI Committee 232, "Fly Ash and Natural Pozzolans in Concrete", Committee 228, "Nondestructive Testing of Concrete", Committee 214, "Evaluation of Results of Strength Tests of Concrete", and Committee 123, "Research". He was also chairman the ASCE technical committee "Emerging Materials" ( ). ACI member Rudolph N. Kraus is Assistant Director, UWM Center for By-Products Utilization, Milwaukee, WI. He has been involved with numerous projects on the use of byproduct materials including utilization of used foundry sand and fly ash in CLSM (Controlled Low Strength Materials), evaluation and development of CLSM, evaluation of lightweight aggregates, and use of by-product materials in the production of dry-cast concrete products. Dr. Shiw S. Singh is Research Associate, UWM Center for By-Products Utilization, Milwaukee, WI. He completed his Ph.D. from University of Wisconsin-Madison in biomechanics. His research interests include solid mechanics, strength and durability of composite materials including cement-based materials, and remedial investigation of sites contaminated with hazardous materials. Parisha P. Chanodia is pursuing her Master of Science degree in Structural Engineering at the University of Wisconsin-Milwaukee. Her research interests include by-products utilization in cement-based materials. 2

4 INTRODUCTION Wood ash is usually generated by saw mills, pulp mills, and the wood-products industry, by burning a combination of wood products, such as bark, twigs, knots, chips, etc. with other supplementary fuels such as coal, oil, natural gas, and coke to generate electricity and/or steam required for their manufacturing processes. Therefore, the resulting ash is sometimes referred to as combined-fuel ash (CFA). A majority of such CFAs generated in the USA is either landfilled or applied on land as a soil supplement. Landfilling is becoming very restrictive and costly while land application is also restricted because of the presence of undesirable elements and/or high alkalinity. Some studies [1-8] have been reported toward evaluating physical and chemical properties of wood ash or CFAs. Based on these properties, a number of constructive use options such as pollution control [3], land application [9,10,11], construction materials [13,14], have been reported. However, most of these applications consume very limited amounts of CFAs due to low-volume uses resulting from environmental restrictions or low economic benefits. More recently, Naik and his colleagues [8,15] indicated that large amounts of CFAs can be used in cement-based materials such as CLSM, low and medium-strength concrete, masonry products, roller-compacted concrete (RCC) pavement, road base materials, blended cements, etc. However, technology for manufacturer of these materials using CFAs is yet to be established. Large volumes of CFAs would be consumed in the manufacture of CLSM. Depending upon intended use, CLSM can be proportioned for compressive strength up to 8.3 MPa (1,200 psi) at the age of 28 days. CLSM can be used for foundations, bridge abutments, buildings, retaining 3

5 walls, utility trenches, etc. as backfill; as embankments, grouts, abandoned tunnels and mine fillings for stabilization of such cavities, etc. CLSM mixture flows like a liquid, and supports like a solid due to its self-setting and hardening behavior. It can typically harden within a few hours of placement. For excavatable CLSM, mixtures should be proportioned to attain compressive strength in the range of 0.4 to 0.7 MPa (50 to 100 psi) at the 28-day age. CLSM can provide cost-effective alternatives to conventional compacted granular backfill or structural fill materials (soil or other granular materials). This is primarily due to lower cost of labor and significantly reduced time required for placement compared to the cost of placing and compacting conventional granular fill materials. The placement of conventional granular fill material requires testing after each lift of 305 to 310 mm (12 to 24 in.), while this is not required for CLSM due to its self-compacting behavior. Since CLSM mixture exhibits very low to negligible settlement after hardening, it provides better support for overlying structures (and/or pavements) and avoids the damage associated with the base/support settlement. Substantial amount of work has been done concerning the use of coal ash in the manufacture of CLSM [16-20]. However, activities have not been reported concerning the use of CFAs in the manufacture of CLSM. Therefore, this investigation was carried out to develop CLSM mixtures for various applications incorporating high volumes of CFAs derived from various sources. EXPERIMENTAL PROGRAM Three series (L, M, and H) of experiments were designed and conducted. Each of these series was developed to obtain a different long-term compressive strength levels at later ages (28 to 91 4

6 days). CLSM mixtures developed for the project were 0.3 to 0.7 MPa (50 to 100 psi) for Series L, low-strength mixtures; 0.7 to 3.4 MPa (100 to 500 psi) for Series M, medium-strength mixtures; and 3.4 to 8.3 MPa (500 to 1200 psi) for Series H, high-strength mixtures. MATERIALS Materials utilized for this project consisted of CFA, cement, fine aggregate, coarse aggregate, and coal fly ash. Each material was characterized for physical and chemical properties in accordance with the appropriate ASTM standards. The detailed data on properties of these materials are reported elsewhere [14]. Summary data is provided in Tables 1 and 2. Five different sources of CFA were used for this project. Each CFA was characterized for physical properties such as fineness (ASTM C 430), strength activity index with cement (ASTM C 109), water requirement (ASTM C 109), autoclave expansion (ASTM C 151), and specific gravity (ASTM C 188). Each CFA was also tested for chemical properties which included determination of oxides, basic chemical elements, and mineralogy. The physical and chemical properties of CFA are given in Tables 1 and 2, respectively. One source of fine aggregate was utilized in this investigation for the high-strength (Series H) CLSM mixtures. Physical properties of the sand were determined per ASTM C 33 requirements for the following properties: unit weight (ASTM C 29), specific gravity and absorption (ASTM 5

7 C 128), fineness (ASTM C 136), material finer than #200 sieve (ASTM C 117), and organic impurities (ASTM C 40). Type I cement was used throughout this investigation. Cement was tested per ASTM C 150 requirements for air content (ASTM C 185), fineness (ASTM C 204), autoclave expansion (ASTM C 151), compressive strength (ASTM C 109), time of setting (ASTM C 191), and specific gravity (ASTM C 188). All CLSM mixtures were batched in the laboratory of the UWM Center for By-Products Utilization. The low-strength CLSM (Series L) mixtures consisted of CFA, ASTM Type I cement, and water. The medium-strength CLSM (Series 2) mixtures consisted of CFA, an increased amount of ASTM Type I cement, and water. The high-strength CLSM (Series H) mixtures consisted of CFA, ASTM Type I cement, sand, and water. These CLSM mixtures were proportioned to maintain a practical value of flow in the range of approximately 250 mm 50 (10 2 in.). MANUFACTURING OF CLSM All CLSM ingredients were manually loaded in a 2.7 m 3 (9 ft 3 ) rotating drum concrete mixer. The required amount of cement together with one-half the specified quantity of fly ash or sand was loaded into the mixer and mixed for three minutes. Three-quarters of the specified water was then added to the mixer and then mixed for an additional three minutes. The remaining CFA 6

8 or sand, and water was added to the mixer and then mixed for five more minutes. Additional water was added in the mixture as needed for achieving the desired flow, prior to discharging the CLSM for testing. Whenever additional water was added to obtain the specified fresh CLSM characteristics, the CLSM mixture was mixed for an additional five minutes. The resulting mixture was then discharged into a pan for further testing and evaluation. SPECIMEN PREPARATION AND TESTING Fresh CLSM mixtures were tested for properties such as air content (ASTM D 6023), flow (ASTM D 6103), unit weight (ASTM D 6023), and setting (ASTM D 6024). Ambient air temperature was also measured and recorded. For each mixture, CLSM test specimens were prepared for compressive strength (ASTM D 4832), water permeability (ASTM D 5084), and setting and hardening tests. Compressive strength of 150 x 300-mm (6 x 12-in) cylindrical specimens was determined at the 3-, 7-, 14-, 28-, and 91-day ages. Permeability was tested at the ages of 28 and 91 days using 100 x 100-mm (4 x 4-in) cylindrical specimens. The amount of bleed water and level of the solids (settlement) of CLSM mixtures were also measured in a 150 x 300-mm (6 x 12-in.) cylinder. All test specimens were cast in accordance with ASTM D These specimens were typically cured for one day in their molds in the UWM-CBU laboratory at about 24 2 C (75 2 F). These specimens were then demolded and placed in a standard moist-curing room maintained at 100% R.H. and 23 1 C (73 2 F), temperature until the time of test (ASTM D 4832). The setting characteristics of the CLSM mixtures were determined using specimens cast in molds, approximately 300 x 300 x 75-mm (12 x 12 x 3-in.). The CLSM 7

9 was cast directly into the mold and left uncovered for the entire measurement period. The setting characteristics were determined in accordance with ASTM D This method measures diameter of an impression by a spherical steel ball of the Kelly Ball apparatus. Per ASTM D 6024, a CLSM mixture becomes suitable to support load when a maximum diameter of impression of 76 mm (3 in.) is reached. This value was considered too high for the cylinders to be safely demolded without damaging the test specimens. Based upon comparing the setting consistency of the CLSM, as cast in the cylinder molds, a more reasonable value was considered to be approximately 50 mm (2 in.). RESULT AND DISCUSSION Fresh CLSM Properties Mixture proportions and fresh CLSM properties for Series L CLSM mixtures are given in Table 3. Flow of all the Series L mixtures were approximately 250 mm (10 in.). Unit weight of the mixtures varied between 1,195 to 1,724 kg/m 3 (74.6 to lb/ft 3 ). Mixture 3-L (CFA Source W-3) had the highest unit weight of 1,726 kg/m 3 (107.6 lb/ft 3 ) while Mixture 2-L (CFA Source W-2) exhibited the lowest unit weight of 1,195 kg/m 3 (74.6 lb/ft 3 ). The remaining mixtures had unit weight of approximately 1,323 to 1,371 kg/m 3 (82.6 to 85.6 lb/ft 3 ). The unit weight of the mixtures agrees with the physical properties of the CFA materials; the mixture containing CFA with the lowest specific gravity also produced the lowest CLSM unit weight. 8

10 Mixture proportions and fresh properties for Series M mixtures are shown in Table 4. Similar to the Series L mixtures, unit weight of the mixtures varied in agreement with the specific gravity of the CFA material. The water demand for the Series M mixtures was similar to that for the Series L mixtures. The flow of the Series M mixtures was mm ( in.). The unit weight followed the same general trend as observed for the Series L mixtures. This was expected since only the quantity of cement was increased for these mixtures compared to the Series L mixtures. Mixture proportions and fresh properties of the Series H mixtures are given in Table 5. These mixtures contained concrete sand to develop relatively high-strength. The water demand to obtain the design flow of approximately 250 mm (10 in.) decreased relative to Series L mixtures which did not contain sand. The required amount of water was approximately 356 to 534 kg/m 3 (600 to 900 lb/yd 3 ) for the Series H mixtures, compared to 475 to 712 kg/m 3 (800 to 1,200 lb/yd 3 ) for the Series L or Series M mixtures without fine aggregate. Unit weights of the Series H mixtures were also significantly higher than the lower-strength mixtures. The values of unit weight ranged from 1,602 to 1,735 kg/m 3 (100 to 127 lb/ft 3 ) for high-strength mixtures and from 1,602 to 1,762 kg/m 3 (75 to 110 lb/yd 3 ) for the low-strength mixtures. The increase in the unit weight was attributed to the higher specific gravity of the sand relative to the CFA. Bleedwater is given as the depth of water present at the top of a 150 x 300 mm (6 x 12 in.) cylinder filled with CLSM. The bleedwater provides an indication of the cohesiveness of the CLSM mixture. Minimizing the amount of bleedwater is desirable to minimize potential 9

11 leaching of elements and escape of bleedwater from the excavation being filled. Bleedwater measurements of the low-strength, Series L, CLSM mixtures showed that initially, bleedwater accumulated to a depth of 1.5 to mm (1/16 to 3/8 in.), but quickly dissipated after 4 to 8 hours (Table 6). Table 7 shows that the bleedwater of the medium-strength, Series M, CLSM mixtures. Bleedwater after one hour ranged from zero to 12.5 mm (1/2 in.) in depth. The bleedwater also did not dissipate as quickly as for the low-strength CLSM mixtures. Mixtures 1-M, 4-M and 5- M still had to 11.1 mm (1/8 to 7/16 in.) of bleedwater remaining after 24 hours. Except mixtures 4-H and 5-H, Series H CLSM mixtures did not exhibit any bleedwater beyond 24 hours (Table 8) SETTLEMENT The settlement of the CLSM is the measured level of the solidified CLSM using the top of a 150 x 300 mm (6 x 12 in.) cylinder as the reference point. The settlement measurements would indicate any potential to shrink or expand and the amount of visible cracking on the surface which may lead to the inflow of water into the CLSM. The settlement of the low-strength, Series L CLSM, mixtures showed a slight shrinkage of Mixtures 1-L, and 5-L, while the level of Mixture 4-L remains relatively constant (Table 9). Two of the mixtures exhibited expansion, Mixtures 2-L and 3-L. Mixture 3-L showed a slight expansion of approximately mm (3/8 in.) which offset the initial settlement of the CLSM. A large expansion occurred for Mixture 2-L. Mixture 2-L (CFA Source W-2) visibly expanded as soon as placed into the cylinder molds and expanded over 25 mm in one hour. Precautions must be taken when using Mixture 2-L due to 10

12 the significant expansion. Placing this mixture in a confined volume could lead to internal pressure that would have to be accounted for in the design. However, the expansive characteristics may be of use when filling a space such as an abandoned tank or pipeline to assure that no voids remain. The settlement data of medium-strength CLSM mixtures are given in Table 10. The settlement or expansion of the medium-strength Series M mixtures was lower compared to the low-strength, Series L CLSM except for Mixture 2-M, which had increased expansion. This mixture used the same source of CFA as used in Mixture 2-L, Source W-2. The increased expansion of this mixture may indicate a reaction with the cement since the cement content of 2-M mixture has significantly increased over that used for Mixture 2-L. The settlement data of the high-strength CLSM is given in Table 11. These mixtures show settlement except for Mixture 2-H, containing CFA Source W-2, which now exhibited a slight shrinkage rather than expansion. This mixture has a high cement content, 205 kg/m 3 (345 lb/yd 3 ), but sand has been introduced into the mixture. The presence of sand in the mixture may provide a confining effect for the expansion product since the unit weight of the CLSM mixture has increased over 481 kg/m 3 (30 lb/ft 3 ) from that of Mixture 2-L or 2-M. Setting and Hardening Characteristics 11

13 The setting characteristics of the CLSM mixtures are shown in Figs. 1 through 3. Setting of the CLSM mixtures have been established for two different levels of imprint diameters of 50 mm (2 in.) and 25 mm (1 in.). Setting of the low-strength Series L mixtures (Fig. 1) ranged from approximately 24 to 96 hours to obtain a diameter of 50 mm (2 in.) to approximately 24 to over 60 hours to obtain a diameter of imprint of 25 mm (1 in.). Mixture 5-L exhibited a significant delay in setting from the 50 mm (2 in.) to the 25 mm (1 in.) level, almost 200 hours. Other mixtures set from the 50 mm (2 in.) to the 25 mm (1 in.) imprint diameter in approximately 60 hours. The source of CFA used for Mixture 5-L (Source W-5) seemed to delay the final setting of the CLSM. The setting characteristics of the medium-strength Series M mixtures are given in Fig. 2. As expected, the time of setting of the CLSM to obtain a 50 mm (2 in.) imprint diameter was less than the Series L mixtures, approximately 12 to 60 hours versus 24 to 96 hours. Similar to the Series L, the time to reach the 25 mm (1 in.) imprint diameter was much longer for the mixture containing CFA Source W-5, Mixture 5-M, than for the other medium-strength CLSM mixtures. The medium-strength Series M mixtures set to the 25 mm (1 in.) diameter in 40 to 75 hours, while Mixture 5-M set to the same level in over 240 hours. The time of setting for the highstrength Series H mixtures (Fig. 3) to the 50 mm (2 in.) imprint level was 10 to 20 hours while setting time to reach the 25 mm (1 in.) imprint level was 24 to 40 hours for Mixtures 1-H through 4-H. Again the CLSM mixture with CFA Source W-5 (Mixture 5-H) had the longest setting time to reach the 25 mm (1 in.) level, over 72 hours. These setting results indicate that for CLSM 12

14 incorporating CFA Source W-5, an accelerator should be used to control the final setting time to acceptable levels. Compressive Strength of CLSM Mixtures The compressive strength data for the low-strength CLSM mixtures are given in Table 12. The compressive strength results at the age of 28 days indicate that four of the mixtures 1-L, 2-L, 3-L, and 4-L achieved satisfactory strength levels. At 28 days these mixtures had compressive strengths of 0.2 to 0.3 MPa (35 to 50 psi). Mixture 5-L (CFA Source W-5) exhibited compressive strength ranging from 0.5 to 1.2 MPa (75 to 170 psi) at 28 days, exceeding the design strength range of 0.7 MPa (100 psi). This indicates that the amount of cement used for Mixture 5-L, 95 kg/m 3 (160 lb/yd 3 ), should be reduced for future mixtures to maintain long-term compressive strengths below 0.7 MPa (100 psi). The compressive strength data for the medium-strength Series M mixtures are given in Table 13. These mixtures were designed and proportioned to achieve compressive strengths of approximately 0.7 to 3.4 MPa (100 to 500 psi). The compressive strengths of all mixtures at the age of 28 days were in the range of approximately 0.7 to 1.4 MPa (100 to 200 psi). The compressive strength of mixture 3-M at the age of 91 days increased to 5.3 MPa (765 psi) while other mixtures had compressive strengths of 1.1 to 2.7 MPa (165 to 390 psi). The strength increase in Mixture 2-M indicates that a later age reaction occured in the CLSM when using this source of CFA. This mixture has the same source of CFA (W-2) that exhibited expansion in the 13

15 settlement tests. This CFA source, when used in CLSM, should be carefully evaluated for applications where setting and long-term strengths gains are not of concern. The compressive strength data for the high-strength Series H CLSM mixtures are shown in Table 14. All Series H Mixtures exhibited a significant increase in compressive strength between the ages of 28 and 91 days. Mixtures 1-H, 3H, 4-H, and 5-H achieved 91-day compressive strengths that met the design strength range. Mixture 2-H (CFA Source W-2) showed a large increase in compressive strength between 28 and 91 days, to 8.6 MPa (230 to 1250 psi). This compressive strength exceeded the maximum specified for CLSM and indicates that the amount of cement could be reduced slightly. Similar to the other Series L and Series M mixtures containing CFA Source W-2, the long-term increase in compressive strength should be evaluated and accounted for when designing fill applications. Water Permeability of CLSM Mixtures The permeability of the Series L mixtures are shown in Table 15. The permeability value varied from 15 x 10-6 cm/s to 110 x 10-6 cm/s at the age of 28 days. The permeability data for Series M CLSM mixtures are shown in Table 16. The permeability values varied from 5 x 10-6 cm/s to 510 x 10-6 cm/s at the age of 28 days. The permeability value decreased substantially at the age of 91 days due to the increase in the maturity of concrete resulting from increased amount of C- S-H formation in the CLSM matrix and thus improving the microstructure of the material. At the 14

16 age of 91 days, permeability varied from 0.1 x 10-6 cm/s to 350 x 10-6 cm/s. Mixtures for 2-M (CFA Source W-2) exhibited the highest permeability. The permeability data for the H CLSM Mixtures are shown in Table 17. The permeability decreased with age due to the densification in the material. Series H CLSM specimens mixtures attained permeability ranging from 2 x 10-6 cm/s to 120 x 10-6 cm/s at the age of 28 days and from 1 x 10-6 cm/s to 38 x 10-6 cm/s at the age of 91 days. CONCLUSION Based on data collected in this investigation, the following conclusions may be drawn. The physical and chemical properties of the combined fuel ashes were significantly influenced by their source. Although all combined fuel ashes used in this work did not conform to the requirements of ASTM C 618 Class C or Class F coal fly ash, they are suitable for use as a primary ingredient of flowable CLSM. 15

17 Fresh CLSM unit weight generally decreased when CFA content or water to cementitious materials ratio was increased. Compressive strength of CLSM mixtures increased with age. CLSM mixtures meeting ACI 229 requirements can be proportioned using large amounts of CFA for strength levels up to 8.3 MPa (1,200 psi) at the age of 28 to 91 days. The permeabilities of the CLSM mixtures made with CFA decreased with increasing age and compressive strength. The permeability values of the CLSM mixtures incorporating CFA was generally lower than that normally observed for compacted clay. ACKNOWLEDGEMENT The authors express their deep sense of gratitude to the UWS/RMDB Solid Waste Recovery Research Program, Madison, WI, and its Program Manager Eileen Norby. Other sponsors of this research project were: Consolidated Papers, Inc. (Stora Enso North America), Wisconsin Rapids, WI; National Council for Air and Stream Improvement (NCASI), Kalamazoo, MI; Weyerhaeuser Company, Rothschild, WI and Tacoma, WA; Wisconsin Electric Power Company, Milwaukee, WI; and Wisconsin Public Service Corporation, Green Bay, WI. Special appreciation is expressed to Ms. Lori Pennock and Bruce Ramme for their interest in this project and monitoring project progress and achievements. Thanks are also due to the UWM Center for 16

18 By-Products Utilization laboratory staff for their contributions in gathering and analysis of test data for this project. The Center was established in 1988 with a generous grant from the Dairyland Power Cooperative, La Crosse, WI; Madison Gas and Electric Company, Madison, WI; National Minerals Corporation, St. Paul, MN; Northern States Power Company, Eau Claire, WI; Wisconsin Electric Power Company, Milwaukee, WI; Wisconsin Power and Light Company (Alliant Energy), Madison, WI; and, Wisconsin Public Service Corporation, Green Bay, WI. Their financial support, and support from the Manitowoc Public Utilities, Manitowoc, WI is gratefully acknowledged. LIST OF REFERENCES 1. Etiegni, L., Wood Ash Recycling and Land Disposal, Ph.D. Thesis, Department of Forest Products, University of Idaho at Moscow, Idaho, USA, June 1990, 174 pages. 2. Etiegni, L., and Campbell, A. G., Physical and Chemical Characteristics of Wood Ash," Bioresource Technology, Elsevier Science Publishers Ltd., England, UK, Vol. 37, No. 2, 1991, pp

19 3. National Council for Air and Stream Improvement, Inc. (NCASI), Alternative Management of Pulp and Paper Industry Solid Wastes, Technical Bulletin No. 655, NCASI, New York, NY, November 1993, 44 pages. 4. Campbell, A. G., Recycling and Disposing of Wood Ash, TAPPI Journal, TAPPI Press, Norcross, GA, Vol. 73, No. 9, September 1990, pp Mishra, M. K., Ragland, K. W., and Baker, A. J., Wood Ash Composition as a Function of Furnace Temperature, Biomass and Bioenergy, Pergamon Press Ltd., UK, Vol. 4, No. 2, 1993, pp Steenari, B. M., and Lindqvist, O., Co-combustion of Wood with Coal, Oil, or Peat-Fly Ash Characteristics, Department of Environmental Inorganic Chemistry, Chalmers University of Technology, Goteborg, Sweden, Report No. ISSN OCLC , Vol. No. 1372, 1998, pp Steenari, B. M., Chemical Properties of BC Ashes, Report No. ISBN , Department of Environmental Inorganic Chemistry, Chalmers University of Technology, Goteborg, Sweden, April 1998, 72 pages. 18

20 8. Naik, T. R., Tests of Wood Ash as a Potential Source for Construction Materials, Report No. CBU , Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, Milwaukee, August 1999, 61 pages. 9. Meyers, N. L., and Kopecky, M. J., Industrial Wood Ash as a Soil Amendment for Crop Production, TAPPI Journal, TAPPI Press, Norcross, GA, 1998, pp Nguyen, P., and Pascal, K. D., Application of Wood Ash on Forestlands: Ecosystem Responses and Limitations, Proceeding of the 1997 Conference on Eastern Hardwoods, Resources, Technologies, and Markets, Forest Product Society, Madison, WI, April 21-23, 1997, pp

21 11. Bramryd, T. and Frashman, B., Silvicultural Use of Wood Ashes Effects on the Nutrient and Heavy Metal Balance in a Pine (Pinus Sylvestris, L.) Forest Soil, Water, Air and Soil Pollution Proceeding of the th International Conference on Acidic Deposition: Science and Policy, Acid Reign 95, Part 2, Kluwer Academic Publishers, Dordrecht Netherland, Vol. 85, No. 2, June 26-30, 1995, pp Naylor, L. M., and Schmidt, E. J., Agricultural Use of Wood Ash as a Fertilizer and Liming Material, TAPPI Journal, TAPPI Press, Norcross, GA, October 1986, pp Mukherji, S. K., Dan, T. K., and Machhoya, B. B., Characterization and Utilization of Wood Ash in the Ceramic Industry, International Ceramic Review, Verlag Schmid GmbH, Freiburg, Germany, Vol. 44, No. 1, 1995, pp Kraus, R.N., and Naik, T.R., Use of Wood Ash for Structural Concrete and Flowable CLSM, Report No. CBU , UWM Center for By-Products Utilization, University of Wisconsin Milwaukee, October 2000, 117 pages. 15. Naik, T. R., Ramme, B. W., and Kolbeck, H. J., Filling Abandoned Underground Facilities with CLSM Fly Ash Slurry, ACI Concrete International: Design and Construction, Vol. 12, No. 7, July 1990, pp

22 16. Naik, T. R., Sohns, L. E., and Ramme, B. W., "Controlled Low Strength Material Produced with High-Lime Fly Ash," Proceedings of the Ninth ACAA International Ash Utilization Symposium, Orlando, FL, January 1991, pp Ramme, B. W., Naik, T. R., and Kolbeck, H. J., "Use of CLSM Fly Ash Slurry for Underground Facilities," ASCE Proceedings on Utilization of Industrial By-Products for Construction Materials, October 1993, pp Naik, T. R. and Singh, S. S. Permeability of Flowable Slurry Materials Containing Foundry Sand and Fly Ash," ASCE Journal of Geotechnical and Geoenvironmental Engineering, May 1997, pp

23 Table 1 - Physical Properties of CFAs TEST PARAMETER W-1 W-2 W-3 W-4 W-5 ASTM C 618 SPECIFICATIONS CLASS C CLASS F CLASS N Retained on No.325 sieve (%) max 34 max 34 max Strength Activity Index with Cement (% of Control) 3-day 7-day 28-day * 83.3* 78.7* min 75 min 75 min 75 min 75 min 75 min Water Requirement (% of Control) * max 105 max 115 Autoclave Expansion (%) * ±0.8 ± max Unit Weight, kg/m 3 (lb/ft 3 ) 545 (34.0) 412 (25.7) 1376 (85.9) 509 (31.8) 162 (10.1) Specific Gravity Variation from Mean (%) Fineness Specific Gravity N.A. 0.4 N.A. 0.4 N.A. N.A. N.A. 0.7 N.A max 5 max 5 max 5 max 5 max 5 max *Material passing No. 100 (150 um) sieve was used for this test. 19

24 Table 2 - Analysis for Oxides, SO 3, and Loss on Ignition for CFAs OXIDES, SO 3, AND LOSS ON IGNITION ANALYSIS, (%) Analysis Parameter W-1 W-2 W-3 W-4 W-5 ASTM C-618 Requirements Class C Class F Class N Silicon Dioxide, SiO 2 Aluminum Oxide, Al 2 O 3 Iron Oxide, Fe 2 O SiO 2 + Al 2 O 3 + Fe 2 O Min 70 Min 70 Min. Calcium Oxide, CaO Magnesium Oxide, MgO Titanium Oxide, TiO 2 Potassium Oxide, K 2 O Sodium Oxide, Na 2 O Sulfite, SO Max 5.0 Max 4.0 Max. Loss on Ignition, LOI (1000? C) Max 6.0 Max 10.0 Max. Moisture Max 3.0 Max 3.0 Max. Available Alkali, Na 2 O, (ASTM C-311) Max 1.5 Max 1.5 Max. 20

25 21

26 Table 3 - Mixture Proportions for the Series L CLSM Mixtures Mix No. 1-L 2-L 3-L 4-L 5-L Laboratory Mixture Designation N-1L DC-1L R-1L B4-1L B5-1L Fly Ash Source W-1 W-2 W-3 W-4 W-5 Fly Ash (%) Cement, kg/m 3 (lb/yd 3 ) 77 (130) 89 (150) 53 (90) 56 (95) 95 (160) Fly Ash, kg/m 3 (lb/yd 3 ) 641 (1080) 469 (790) 1187 (2000) 662 (1115) 498 (840) Water, W kg/m 3 (lb/yd 3 ) 626 (1055) 635 (1070) 481 (810) 656 (1105) 730 (1230) [W/(C+A)] Air Temperature, C ( F) 22.2 (72) 22.2 (72) 22.2 (72) 22.2 (72) 22.2 (72) Fresh CLSM Temperature, C ( F) 23.3 (74) 23.3 (74) 23.9 (75) 22.8 (73) 24.4 (76) Flow, mm (in.) 241 (9 ½) 254 (10) 254 (10) 254 (10) 254 (10) Air Content (%) Unit Weight, kg/m 3 (lb/ft 3 ) 1344 (83.9) 1195 (74.6) 1724 (107.6) 1371 (85.6) 1323 (82.6) 22

27 Table 4 - Mixture Proportions for the Series M CLSM Mixtures Mix No. 1-M 2-M 3-M 4-M 5-M Laboratory Mixture Designation N-1 DC-1 R-1 B4-1 B5-1 Fly Ash Source W-1 W-2 W-3 W-4 W-5 Cement, kg/m 3 (lb/yd 3 ) 187 (315) 228 (385) 101 (170) 157 (265) 125 (210) Fly Ash, kg/m 3 (lb/yd 3 ) 611 (1030) 400 (675) 1133 (1910) 617 (1040) 445 (750) Water, W kg/m 3 (lb/yd 3 ) 602 (1015) 596 (1005) 510 (860) 635 (1070) 721 (1215) [W/(C+A)] Flow, mm (in.) 273 (10 ¾) 260 (10 ¼) 254 (10) 260 (10 ¼) 260 (10 ¼) Air Content (%) Air Temperature, C ( F) 25.5 (78) 25.5 (78) 25.5 (78) 26.1 (79) 26.1 (79) Fresh CLSM Temperature, C( F) 22.2 (72) 27.8 (82) 25.5 (78) 31.1 (88) 22.2 (72) Unit Weight, kg/m 3 (lb/ft 3 ) 1394 (87) 1234 (77) 1762 (110) 1410 (88) 1298 (81) 23

28 Table 5 - Mixture Proportions for the Series H CLSM Mixtures Mix No. 1-H 2-H 3-H 4-H 5-H Laboratory Mixture Designation N-2 DC-2 R-2 B4-2 B5-2 Fly Ash Source W-1 W-2 W-3 W-4 W-5 Cement, kg/m 3 (lb/yd 3 ) 169 (285) 205 (345) 196 (330) 175 (295) 157 (265) Fly Ash, kg/m 3 (lb/yd 3 ) 427 (720) 205 (345) 537 (905) 392 (660) 353 (595) Water, W kg/m 3 (lb/yd 3 ) 418 (705) 430 (725) 359 (605) 484 (815) 540 (910) [W/(C+FA)] SSD Fine Aggregate, kg/m 3 (lb/yd 3 ) 774 (1305) 828 (1395) 946 (1595) 706 (1190) 611 (1030) Flow, mm (in.) 273 (10 ¾) 260 (10 ¼) 273 (10 ¾) 260 (10 ¼) 260 (10 ¼) Air Content (%) Air Temperature, C ( F) 25.6 (78) 26.1 (79) 25.6 (78) 25.6 (78) 24.4 (76) Fresh CLSM Temperature, C ( F) 23.3 (74) 27.8 (82) 28.9 (84) 26.7 (80) 22.8 (73) Unit Weight, kg/m 3 (lb/ft 3 ) 1794 (112) 1660 (104) 2035 (127) 1762 (110) 1666 (104) 24

29 Table 6 - Bleedwater of the Series L CLSM Mixtures Mixture No. Bleedwater mm (in) * 1 hour 4 hour 8 hour 24 hour 2 days 3 days 2 days 1-L 2-L 3.2 (1/8) L 0 4-L (1/8) L *Average of three readings Table 7 - Bleedwater of the Series M CLSM Mixtures Mixture No. Bleedwater, mm (in) * 1 hour 4 hour 8 hour 24 hour 2 days 3 days 7 days 1-M (½) (1/8) 2-M M 3.2 (1/8) M (1/8) 5-M (1/2) (7/16) *Average of three readings 25

30 Table 8 - Bleedwater of the Series H CLSM Mixtures Mixture No. Bleedwater, mm (in.) * 1 hour 4 hour 8 hour 24 hour 2 days 3 days 1-H (1/8) 2-H H (1/8) 4-H (5/16) (1/2) 5-H * Average of three readings Table 9 - Settlement of the Series L CLSM Mixtures Mixture No. Settlement, mm (in.)* 1 hour 4 hour 8 hour 24 hour 2 days 3 days 7 days 14 days 1-L /8 (1/2) (1/2) (5/16) 2-L (1-1/16)* (1-15/16)** (1-13/16)** (1-13/16)** (1-15/16) (1-15/16)* 3-L L L (1/8) *Average of three readings 26

31 **Values indicate CLSM expansion 27

32 Table 10 - Settlement of the Series M CLSM Mixtures Mixture No. Settlement, mm (in.) * 1 hour 4 hour 8 hour 24 hour 2 days 3 days 7 days 14 days 1-M (1/2) 2-M (1-11/16)** (2)** (2-3/16)** (2-7/16)** (2-7/16)** (2-7/16)** 3-M (1/8) M (1/2) (1/2) (7/16) (1/2) (1/2) (1/2) (1/2) 5-M (1/2) (7/16) (1/8) *Average of three readings **Values indicate CLSM expansion Table 11 - Settlement of the Series H CLSM Mixtures Mixture No. Settlement, mm (in.)* 1 hour 4 hour 8 hour 24 hour 2 days 3 days 7 days 14 days 1-H (1/8) 2-H H (1/8) 4-H (1/2) (1/2) (1/2) (7/16) (7/16) 5-H 6.4 *Average of three readings 28

33 Table 12 - Compressive of the Series L CLSM Mixtures Mixture No. Compressive Strength, kpa (psi) * 3-day 7-day 14-day 28-day 91-day 1-L (15) (25) (30) (55) (70) 2-L (10) (20) (20) (35) (55) 3-L (20) (25) (30) (60) (140) 4-L (15) (25) (30) (40) (70) 5-L (20) (70) (75) (170) (260) *Average of three readings Table 13 - Compressive of the Series M CLSM Mixtures Mixture No. Compressive Strength, kpa (psi) * 3-day 7-day 14-day 28-day 91-day 1-M 310 (45) 340 (50) 480 (70) 1400 (200) 2840 (390) 2-M 450 (65) 550 (80) 720 (105) 970 (140) 2690 (765) 3-M 450 (65) 660 (95) 760 (110) 1280 (185) 1590 (230) 4-M 210 (30) 660 (95) 900 (130) 1450 (210) 2550 (370) 5-M 170 (25) 340 (50) 620 (90) 720 (105) 1140 (165) *Average of three readings 29

34 Table 14 - Compressive of the Series H CLSM Mixtures Mixture No. Compressive Strength, kpa (psi)* 3-day 7-day 14-day 28-day 91-day 1-H 830 (120) 1380 (200) 2340 (340) 3240 (470) 6650 (965) 2-H 720 (105) 1070 (155) 1140 (165) 1590 (230) 8620 (1250) 3-H 1900 (275) 2280(330) 2480 (360) 3100 (450) 4000 (580) 4-H 850 (120) 1520 (220) 2520 (365) 3590 (520) 6960 (1010) 5-H 660 (95) 1480 (215) 2210 (320) 2210 (320) 4240 (615) *Average of three readings Table 15 - Permeability of the Series L CLSM Mixtures Mixture No. Permeability (cm/sec)* 28-day 1-L 100 x L 54 x L 15 x L 35 x L 110 x 10-6 *Average of three readings 30

35 Table 16 - Permeability of Series M CLSM Mixtures Mixture No. Permeability (cm/sec)* 28-day 91-day 1-M 6 x x M 510 x x M 20 x x M 5 x x M 74 x x 10-6 *Average of three readings Table 17 - Permeability of Series H CLSM Mixtures Mixture No. Permeability (cm/sec)* 28-day 91-day 1-H 12 x x H 2 x x H 120 x x H 19 x x H 4 x x 10-6 *Average of three readings 31

36 Diameter of Imprint, mm Diameter of Imprint, mm Mixture 1-L Mixture 2-L Mixture 3-L Mixture 4-L Mixture 5-L ASTM D 6024 Limit 76 mm Age, hours Fig. 1 - Setting Characteristics for the Series L CLSM Mixtures Mixture 1-M Mixture 2-M Mixture 3-M Mixture 4-M Mixture 5-M ASTM D 6024 Limit 76 mm Age, hours Fig. 2 - Setting Characteristics for the Series M CLSM Mixtures 30

37 Compressive Strength, KPa Diameter of Imprint, inches Mixture 1-H Mixture 2-H Mixture 3-H Mixture 4-H Mixture 5-H ASTM D 6024 Limit 76 mm Age, hours Fig. 3 - Setting Characteristics for the Series H CLSM Mixtures Mixture 1-L Mixture 2-L Mixture 3-L Mixture 4-L Mixture 5-L Age, days Fig. 4 - Compressive Strength for Series L CLSM Mixtures 31

38 Compressive Strength, KPa Compressive Strength, KPa Mixture 1-M Mixture 2-M Mixture 3-M Mixture 4-M Mixture 5-M Age, days Fig. 5 - Compressive Strength for the Series M CLSM Mixtures Mixture 1-H Mixture 2-H Mixture 3-H Mixture 4-H Mixture 5-H Age, days Fig. 6 - Compressive Strength for the Series H CLSM Mixtures 32