Compressive Strength of Ternary Blended Cement Sandcrete Incorporating Saw Dust Ash and Oil Palm Bunch Ash

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1 e-issn Volume 2 Issue 10, October 2016 pp Scientific Journal Impact Factor : Compressive Strength of Ternary ed Cement Sandcrete Incorporating Saw Dust Ash and Oil Palm Bunch Ash L. O. Ettu 1, C. T. G. Awodiji 2, H. E. Opara 3, K. N. Onyema 4, and E. K. Ejiogu 5 1,2,4,5 Department of Civil Engineering, Federal University of Technology, Owerri, Nigeria. 3 Department of Civil Engineering, Imo State University, Owerri, Nigeria. 1 Corresponding Author, revloettu@yahoo.com Abstract This work investigated the compressive strength of ternary blended cement sandcrete incorporating saw dust ash () and oil palm bunch ash (). Ordinary Portland cement (OPC) was blended with and by partially replacing OPC with - at five levels, namely 5%, 10%, 15%, 20%, and 25%. For each replacement level, was admixed with at five ratios of 100:0, 95:5, 90:10, 85:15, and 80:20, making a total of 25 OPC-- ternary blends. Nine Sandcrete cubes of 150x150x150mm were produced for each of the 25 ternary blends. Nine cubes containing only OPC were also produced as the control, making a total of 234 sandcrete cubes. A constant cementitious material to sand mix ratio of 1:6 and water to cement ratio of 0.6 were used. Three cubes for each ternary blend and the control were crushed to obtain their compressive strengths at 28, 90, and 150 days. The results showed that the compressive strengths of the ternary blended sandcrete increased at a greater rate than that of the control at 90 days of curing and onwards. At 10% OPC replacement level and to proportion of 80:20, sandcrete strength increased from 5.44N/mm 2 at 28 days of curing to 7.48N/mm 2 at 90 days of curing, indicating 38% increase. The corresponding control sandcrete strengths were 9.77 N/mm 2 and N/mm 2, a strength increase of only 12%. The 90 to 150 day strength values of the OPC-- ternary blended sandcrete for 5% to 15% OPC replacement with - suggest they could be suitable for use in various civil engineering and building works, especially in situations where high early strength is not crucial. Keywords Sandcrete, ternary blended cement, compressive strength, curing age, saw dust ash, oil palm bunch ash I. INTRODUCTION Extensive researches in alternative Ordinary Portland Cement (OPC)-replacing materials using pozzolanic agro bye products are currently on-going so as to both reduce the high cost of OPC and the pollution of the environment associated with its production (Duna & Omoniyi, 2014; Naik & Moriconi, 2009). Previous studies show that many agro bye products could be pozzolanic (Ettu, Osadebe et al., 2013). The compressive strength and durability properties of cement composite can generally be enhanced with the addition of this agro-bye products at a certain optimum replacement level (Safiuddin & Zain, 2006). Habeed and Mahmud (2010) reported that replacing OPC with rice husk ash improved the compressive strength of concrete. Alwash (2013) observed significant improvement on strength and modulus of elasticity of self-compacting concrete at 60 days curing when rice husk ash (RHA) and Metakaolin were used as partial replacement for OPC at 15% replacement level. Ettu, Nwachukwu et al. (2013) suggested that the successful utilization of agro bye products as pozzolanic materials would add commercial value to the otherwise waste products and encourage massive cultivation of the crops for various uses. Two of these agro bye products are of special interest to us in this research, namely saw dust and oil palm bunch. Obilade (2014) explains that sawdust is a bye product of milling, cutting, grinding, drilling, sanding, or otherwise pulverizing timber with a saw or other tool into various shapes and sizes and is commonly used All rights Reserved 5

2 domestic fuel in many parts of South-Eastern Nigeria. The resulting ash is known as sawdust ash (). Oil palm bunch is a bye product from palm oil extraction process. It is usually discarded in palm oil mills after processing the oil palm fruit in many parts of South-Eastern Nigeria. Notable researches show that oil palm bunch ash () could be used as supplementary cementitious material in mortar, sandcrete, and concrete. For instance, Hadi et al. (2015) studied the effect of replacing different portions of cement by fine. They concluded that the cement composite showed higher compressive strength, less water absorption, increased density and lesser soreptivity. Raheem et al. (2012) investigated the use of saw dust ash () as a pozzolan in the production of concrete and found that the compressive strength of concrete with was lower at early stages but improved much at 90 days of curing. They concluded that 5% substitution is adequate to enjoy maximum benefit of strength gain. Elinwa and Mahmud (2002) recommended 10% as the optimum replacement level of for OPC in concrete. Chowdhury et al. (2015) confirmed the presence of some essential pozzolanic compounds in wood ash as required by standards. Munshi & Sharma (2013) studied the effect of using rice straw ash as a partial replacement of cement in mortar and posited that although setting times were delayed with increased amount of cement replacement, there was enhancement of strength of mortar with certain quantity of replacement of cement with rice straw ash. Ettu, Mbajiorgu et al. (2013) investigated the compressive strength of binary blended cement composites containing and found the strength values to be comparable to the control values beyond 90 days of hydration at 5% OPC replacement with. Udoeyo and Dashibi (2002) investigated the use of sawdust ash as concrete material and revealed that there was significant improvement of compressive strength of concrete at prolonged curing age of 90 days. Raheem et al. (2012) suggested that only 5% substitution is adequate to enjoy maximum benefit of strength gain. Raheem and Sulaiman (2013) also studied the use of as partial replacement for OPC in sandcrete blocks. Some units of sandcrete hollow blocks were produced by partially replacing the cement content with 5% to 25% by weight of. The results indicated that at 56 days the compressive strength of blocks with 5% and 10% replacement were 2.33N/mm 2 and 2.04N/mm 2 respectively, both of which surpassed the required standard of 2.00N/mm 2 specified by the National Building Code (2006) for non-load bearing walls. They concluded that only sandcrete blocks with up to 10% replacement can be used for non-load bearing walls. Similarly, Popoola et al. (2015) investigated the compressive strength characteristics of hollow sandcrete blocks with OPC partially replaced by saw dust ash and concluded that up to 10% replacement can be used for non-load bearing walls for 1:8 mix at 28 days curing age and up to 10% replacement for 1:6 mix can be used for both load and non-load bearing walls. Ettu, Ibearugbulem et al. (2013) had earlier investigated the compressive strength of binary blended cement sandcrete containing and found that the 90-day strengths obtained from the binary blended cement sandcrete had compressive strength values close to the control specimen. The current research being reported in this paper investigated the use of varying proportions of saw dust ash () to oil palm bunch ash () as partial replacement to OPC in OPC-- ternary blended cement sandcrete. Satisfactory strength of this ternary blended sandcrete would be particularly useful in making low-cost sandcrete blocks for use in housing projects in various Nigerian communities with plentiful supply of saw dust and oil palm bunch. II. METHODOLOGY Ordinary Portland cement (OPC) with specific gravity of 3.06 and bulk density of 1675 kg/m 3 was used in this work. River sand from a local stream in Owerri was used as fine aggregate. The fine aggregate had specific gravity of 2.64, bulk density of 1675kg/m 3, fineness 2.33, coefficient of uniformity of 2.41, coefficient of gradation of 1.14, and was classified as zone-3 according to BS 882(1992) grading limit for All rights Reserved 6

3 Sawdust was obtained from wood mills in Owerri, South-Eastern Nigeria. It was sun-dried and burnt using a local pit-crucible furnace to obtain the ash. The saw dust ash () was then sieved using 600µm sieve to remove bigger and impure particles. The resultant used for this work had specific gravity of 1.84 and bulk density of 820 kg/m 3. Oil palm bunch was obtained from local oil mill at Mbaise, South-Eastern Nigeria. It was sun-dried, burnt, and processed in a similar way as was saw dust to obtain the oil palm bunch ash () with specific gravity of and bulk density of 865 kg/m 3. Potable water obtained from Federal University of Technology, Owerri was used for this work. Batching was by weight. A constant cementitious material to fine aggregate mix ratio of 1:6 and water to cement ratio of 0.6 was used for the study. Ordinary Portland cement (OPC) was replaced with a combination of and at five replacement levels of 5%, 10%, 15%, 20%, and 25%. For each replacement level, was admixed with at five ratios of 100:0, 95:5, 90:10, 85:15, and 80:20, making a total of 25 OPC-- ternary blends. Nine Sandcrete cubes of 150x150x150mm were produced for each of the 25 ternary blends. Nine cubes containing only OPC were also produced as the control, making a total of 234 sandcrete cubes. Curing was by water sprinkling in a shade for the first three days and by immersion for the rest of the curing period. Three cubes for each ternary blend and the control were crushed to obtain their compressive strengths at 28, 90, and 150 days. The proportioning of and for the 25 ternary blends and the control is shown in Table 1 for 0%, 5%, and 10% - and in Table 2 for 15%, 20%, and 25% -. III. RESULTS AND DISCUSSION The compressive strengths for the 25 ternary blends of OPC-- sandcrete and the control at 28, 90, and 150 days of curing are shown in Table 3 for 0%, 5%, and 10% - and in Table 4 for 15%, 20%, and 25% -. Table 1. Proportioning of and for 0%, 5%, and 10% - 0% OPC replacement (control) % OPC replacement % OPC replacement All rights Reserved 7

4 Table 2. Proportioning of and for 15%, 20%, and 25% - 15% OPC replacement % OPC replacement % OPC replacement Table 3. Compressive strengths of OPC-- sandcrete for 0%, 5%, and 10% - / ratio Compressive strength (N/mm 2 ) 28 days 90 days 150 days 0% OPC replacement (control) % OPC replacement 2 100: : : : : % OPC replacement 7 100: : : : : All rights Reserved 8

5 The results in Tables 3 and 4 reveal a number of interesting points. First, the control samples attained higher compressive strengths at 28 days of curing than the corresponding ternary blended sandcrete for all percentages of replacing OPC with - and for all proportions of and. This could be as a result of the faster hydration process and consequent early strength gain of OPC when compared to agricultural bye product pozzolanic blends. Second, the compressive strengths of the ternary blended sandcrete greatly increased relative to the control at 90 days curing and onwards as the pozzolanic reaction increased, leading to the production of additional Calcium Silicate Hydrate (CSH), the major compound responsible for strength (Ettu et al., 2013). For example, at 10% OPC replacement level and to proportion of 80:20, sandcrete strength increased from 5.44N/mm 2 at 28 days of curing to 7.48N/mm 2 at 90 days of curing, indicating 38% increase. The corresponding control sandcrete strengths were 9.77 N/mm 2 and N/mm 2, a strength increase of only 12%. Third, the strength of the ternary blended sancrete samples continuously decreased with increase in percentage replacement of OPC with - for all curing ages and for all proportions of to. For example, the 150 day strength for to proportion of 90:10 reduced from 9.95 N/mm 2 at 5% OPC replacement to 7.33 N/mm 2 at 25% replacement. This suggests the possibility that not all of the - is involved in the pozzolanic reaction to produce additional CSH; rather, some of the - could simply serve as fillers that does not contribute to strength gain. Table 4. Compressive strengths of OPC-- sandcrete for 15%, 20%, and 25% - / ratio Compressive strength (N/mm 2 ) days 90 days days 15% OPC replacement : : : : : % OPC replacement : : : : : % OPC replacement : : : : : All rights Reserved 9

6 Fourth, the strength of the ternary blended sandcrete also continuously decreased with increase in in the to ratio at all percentage replacement levels and for all curing ages. For example, at 15% OPC replacement with - and for 150 days of curing, the strength decreased from 8.89 N/mm 2 for to proportion of 100:0 to 7.90 N/mm 2 for to proportion of 80:20. This decrease in strength with increase in proportion suggests that is a much weaker pozzolan than and its higher proportion further slows the pozzolanic activity. Fifth, the 90 to 150 day strength values of the OPC-- ternary blended sandcrete, especially for 5% to 15% OPC replacement with -, suggest they could be suitable for use in various civil engineering and building works, especially in situations where high early strength is not crucial. IV. CONCLUSIONS The following five conclusions are pertinent: 1. On the basis of compressive strength, OPC-- ternary blended sandcrete at 5% to 15% OPC replacement with - could be suitable for use in various civil engineering and building works, especially in situations where high early strength is not crucial. 2. The control samples containing 100% OPC attained higher compressive strengths at 28 days of curing than the corresponding OPC-- ternary blended sandcrete for all percentages of replacing OPC with - and for all proportions of to. 3. The compressive strength of OPC-- ternary blended sandcrete continuously decreases with increase in in the to ratio at all percentage replacement levels and for all curing ages. 4. The compressive strength of OPC-- ternary blended sandcrete also continuously decreases with increase in percentage replacement of OPC with - for all curing ages and for all proportions of to. 5. The compressive strengths of OPC-- ternary blended sandcrete greatly increased relative to the control at 90 days curing and onwards. REFERENCES Alwash, J. J. (2013). Self-compacting concrete incorporating rice husk ash and metakaolin. AL-Qadisiya Journal For Engineering Sciences, Vol. 6 (No 2), PP Chowdhury S., Maniar, A., Suganya, O.M. (2015). Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters. Journal of Advanced Research. Vol.6, pp Duna, S. & Omoniyi,T. M. (2014).Investigating the Pozzolanic Potentials of Cowdung Ash in Cement Paste and Mortars.Civil and Environmental Research,Vol.6,pp Elinwa, A. U., & Mahmood, Y. A. (2002). Ash from Timber Waste as Cement Replacement Material. Cement and Concrete Composites, 24(2), Ettu, L. O., Osadebe,N. N.,& Mbajiorgu,M. S. W. (2013f). Suitability of Nigerian agricultural by-products as cement replacement for concrete making. International Journal of Modern Engineering Research (IJMER), Vol.3(2), pp Ettu, L. O., Nwachukwu, K. C.,Arimanwa,J. I., Anyanwu, T. U.,& Okpara,S. O. (2013,d). Strength of blended cement sandcrete & soilcrete blocks containing afikpo rice husk ash and corn cob ash. International Journal of Modern Engineering Research, Vol.3(Issue.3), All rights Reserved 10

7 Ettu, L. O., Mbajiorgu, M. S. W., and Njoku, F. C. (2013). Strength of Binary ed Cement Composites Containing Oil Palm Bunch Ash. International Journal of Engineering Science Invention (IJESI), 2 (4): Ettu, L. O., Ibearugbulem, O. M., Anya, U. C., Awodiji, C. T. G., and Njoku, F. C. (2013). Strength of Binary ed Cement Composites Containing Saw Dust Ash. The International Journal of Engineering and Science (IJES), 2 (4): Habeeb, G. A.,& Mahmud, H. B. (2010). Study on Properties of Rice Husk Ash and Its Use as Cement Replacement Material. Materials Research, 13(2), pp Hadi, F., Awang,H.,& Almulali(2015) The effect of oil palm ash incorporation in foamed concrete.jurnal Teknologi(Science & Engineering)vol.75(5) pp Munshi, S., Dey, G.,& Sharma,R.P (2013). Use of Rice Straw Ash as Pozzolanic Material in Cement. International Journal of Engineering and Technology, Vol. 5(Issue 5), Naik, T.R.,& Moriconi,G. (2009). Environmental-friendly durable concrete made with recycled materials for sustainable concrete construction. Obilade, I. O. (2014). Use of saw dust ash as partial replacement for cement in concrete. International Journal of Engineering Science Invention, Vol. 3(8), PP Popoola, O.C., Ayegbokiki, S.T., & Gambo, M.D. (2015). Study of compressive strength characteristics of hollow sandcrete blocks partially replaced by saw dust ash. International organization of Scientific Research.vol.5(5) pp Raheem, A. A., Olasunkanmi,B. S., & Folorunso,C. S. (2012). Saw Dust Ash as Partial Replacement for Cement in Concrete. organization, technology and management in constructionan international 474 journal, 4(2), pp Raheem, A. A., &Sulaiman, O. K. (2013). Saw dust ash as partial replacement for cement in the production of sandcrete hollow blocks.. International Journal of Engineering Research and Applications, Vol. 3( 4), pp Safiuddin, M.d. and Zain,M.F.M. (2006). Supplementary cementing materials for high performance concrete. BRAC University Journal, Vol. III( 2), pp Udoeyo, F.F., & Dashibi., P.U. (2002). Sawdust ash as concrete material.. Journal of Materials in Civil Engineering. ASCE, Vol. All rights Reserved 11