Effect of the Use of Mound Soil as an Admixture on the Compressive Strength of Concrete

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1 Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 3(6): Scholarlink Research Institute Journals, 2012 (ISSN: ) jeteas.scholarlinkresearch.org Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 3(6): (ISSN: ) Effect of the Use of Mound Soil as an Admixture on the Strength of Concrete O. U. Orie and B. U. Anyata Civil Engineering Department, University of Benin, Benin City, Nigeria. Corresponding Author: O. U. Orie Abstract The paper examined some mechanical properties of mound soil concrete (MSC) to harness its structural property in the construction industry. Mound soil (MS), randomly selected from some habitats of a common tropical specie of termites from Iyeke-Ogba, Nigeria was investigated. The work applied the laboratory investigative methodology. Steel moulds measuring 150mm x 150mm x 150mm were used to cast cube samples from a standard 1:2:4 mix. Water to cement ratio (w/c) was kept constant at 0.55 and the content of mound soil was varied between 0 and 30%. The moulds were demoulded after 24 hours and the samples cured in a tank at 30 0 C and were tested for 7, 14 and 28 days strength. The results showed that the control mix with 0% MS gave a compressive strength of N/mm 2 and slump of 65mm. Addition of 15% mound soil by weight of cement produced N/mm 2 with 24mm slump representing an increase of 21.83% in compressive strength and 36.92% improvement of workability. The paper concludes that MS can be used as an additive in structural concrete for high compressive strength and workability. Keywords: Concrete, Admixtures, Strength, Workability and Economy. INTRODUCTION Concrete is a heterogeneous construction material made of water, cement, fine aggregate, coarse aggregate and sometimes additives. The materials used as admixtures vary depending on the desired property of the concrete. Concrete has an enviable reputation for providing long maintenance-free service. Denis (2000) reported that plain concrete has the potential for lasting virtually for ever. The use of Agricultural and Industrial waste is fast gaining ground in the construction industry. As research is moving more towards making more economic concrete. The development of some cities in Nigeria recently, led to the generation of huge volumes of construction and demolition (C&D) materials. In the past, the inert portions of these C&D materials, such as rock, concrete and soil, had been beneficially reused as fill materials in forming land for the Nation s development. Recycling is one of the most cost effective means of C&D materials. Cost effectiveness without compromising the strength and durability of concrete as well as stability of structures produced from it has predominated resent researches in the construction Industry. Emphasis has been in the use of otherwise by-products. Pons et al (1998), Fox (1989), Snethen and Benson (1998), Sullivan (1997), Ohlheiser (1998) and Hook et al (1998), showed that various by-products can be used in Controlled Low-Strength Material CLSM, for Backfill. Mound soil is soil devoid of any decayed vegetable material. They are built of earth particles which are cemented together forming hard brick-like materials resistant to weathering and difficult to pick (Felix etal, 2000). Felix et-al (2000) also reported that addition of 5% mound soil to a concrete mix of 1:2:4:0.56 (cement: sand: coarse: water) causes an increase of up to 20.35% in compressive strength. Orie and Osadebe (2009) showed that mound soil can be used as a fifth component in concrete. EXERIMENTAL PROGRAMME MATERIALS Crushed granite from Ifon was used, the maximum size of which was 14mm. The grading and properties of the coarse aggregate conformed to BS882. Okhuahe River Sand (OKRS) was used. It consisted of quartzite with the grading and properties conforming to BS882. Mound soil from Iyeke-Ogba area in Edo State of Nigeria was used. It formed the main material on which the investigation was directed. According to the specification of BS3148:1980, potable water was used. Preparation of Samples The materials for the experiment were sourced and transferred to the laboratory where they were allowed to dry. The mound soil was pulverized using wooden 990

2 Mortar and Pestle. Sampling was carried out using the quartering method. METHODS A. Setting Time of Cement The initial and final setting times of the cement were determined with vicat apparatus as specified by BS 4550: part3: (1978) B. Cube Strengths and Water Cement Ratio A standard mixes ratio of 1:2:4 was used to cast cubes of size150mm 150mm 150mm. These ratios were kept constant but first at varying water/cement ratio and then at varying mound soil content. Batching was carried out by weight and the cubes were cast conforming to BS : (1978). Demoulding of samples was done after 24 hours. The samples were then transferred into the curing tank which was maintained at room temperature. The cubes were tested for compressive strength on removal from the curing tank at the required ages, using compression machine to the requirements of BS 1881: Part 115 (1983). The compressive strength ( ) were obtained from the ratio Maximumloa d f c Cross sectionalarea P A (1) RESULTS The results of the experimental work are presented below Table 1: Setting Time of Cement Type of Cement: Burham Portland Cement Consistency 33.75% Initial Setting Time 2hrs 30mins Final Setting Time 3hrs 15mins Table 2: Water Absorption of Coarse Aggregate Weight in air (kg) Weight after 24hrs in water (kg) Absorbed water (kg) = Water absorption (%) Table 3: Specific Gravity Test Mound Soil Fine Aggregate Coarse Aggregate Bottle No. V U Wt. of bottle + water (full) W Wt. of bottle + soil + water W Wt. of bottle + soil W Wt. of Bottle W Wt of added water (W4 - W1) Wt. of water added to soil (W3 - W2) Wt. of soil (W2 - W1) Wt. of water displaced by soil (W4 - W1) - (W3 - W2) = W Specific Gravity of soil (W2 W1) / W Average specific gravity Table 4: Moisture Content and Density Determination of Mound Soil Container No. N18 N80 N19 N7 N17 N21 N2 N90 N22 N31 N13 N15 Wt. of wet soil and container g Wt. of dry soil and container g Wt. of container g Wt. of dry soil (W d) g Wt. of moisture (W m) g Moisture content W m W % d Average moisture content (m) % Dry density g d 3 / cm m

3 Dry Density (g/cm 2 ) Fig.1 Moisture Content/Dry density Relationship of Mound Soil Maximum Dry Density: 1.92g/cm 3 Optimum Moisture Content: 13.7% Average Moisture Content (%) Table 5: Chemical Analysis of Mound Soil Component Unit Fraction ph 6.70 Clay % Silt % 1.3 Sand % 82.9 Fe Mg/kg Zn Mg/kg S Ca Meq/100g 4.64 Mg Meq/100g 0.24 K Meq/100g 0.39 Cation Exchange Capacity Milli equivalent /100g 6.23 E.A (H + +Al 3+ ) Meq/100g 0.2 Table 6: Bulk Density of Fine Aggregate Wt. of empty mould (M 1) 4465g Wt. of mould + soil (M 2) 5961g Wt. of soil (M 2 - M 1) 1496g Height of mould 11.50cm Diameter of mould 10.10cm Volume of mould cm 3 Bulk M M 1 density Volume g / cm Table 7: strength of M. S 0% and w / c for 1:2:4 Mix Slump=65mm 7 days 14 days 28 days Mass (kg) Failure load Mean failure load Strength (N/mm 2 ) Table 8: strength of. S 2.5% M and / c 0.55% w for1:2:4 Mix Slump=45mm 7 days 14 days 28 days Mass (kg) Failure load

4 Table 9: strength of. S 5% M and / c w for 1:2:4 Mix Slump=43mm 7 days 14 days 28 days Mass (kg) Failure load Table 10: strength of. S 7.5% M and / c w for 1:2:4Mix Slump=40mm 7 days 14 days 28 days Mass (kg) Failure load Mean failure load Strength (N/mm 2 ) Table 11: strength of. S 10% M and / c w for 1:2:4 Mix Slump=30mm 7 days 14 days 28 days Mass (kg) Failure load Table 12: strength of M. S 12.5% and w / c for1:2:4 Mix Slump=24mm 7 days 14 days 28 days Mass (kg) Failure load Table 13: strength of M. S 15% and w / c for 1:2:4 Mix Slump=24mm 7 days 14 days 28 days Mass (kg) Failure load Table 14: strength of M. S 20% and w / c for 1:2:4 Mix Slump=25mm 7 days 14 days 28 days Mass (kg) Failure load

5 Table 15: strength of. S 25% M and / c w for 1:2:4 Mix Slump=24.5mm 7 days 14 days 28 days Mass (kg) Failure load Table 16: strength of M. S 30% and w / c for 1:2:4 Mix Slump=24mm 7 days 14 days 28 days Mass (kg) Failure load days 14 days 28 days Mound Soil Content (%) Fig.2 Relationship between Strength Gain and Mound Content (1:2:4:0.55) DISCUSSION The results of the geotechnical properties of the MS used are presented in Tables 1 to 4 and in Figure 1. They showed that MS belongs to class SC (Silty Clay) in the Unified Soil classification. The result of the chemical analysis of the MS is presented in Table 5. It showed that MS contains 4.64 by fraction of calcium (Ca) an element predominant in OPC. The presence of Ca in MS enhanced the complete hydration of OPC and consequently, the development of higher strength in the concrete. The table revealed that MS contains 0.24 Milli equivalents of magnesium. The improved workability of concrete which was observed during the work may be attributed to the presence of this trace element. Tables 7 to 16 and Figure 2 present the effects of MS on the compressive strength of concrete as the fraction of MS is increased in standard 1:2:4 mixes. These results generally showed that MS behaves as a plasticizer. Figures 2 showed that the maximum compressive strength of N/mm 2 was attained by the addition of 15% of MS. This represents an increase of 21.83% in the compressive strength of the mix. The result is in agreement with the literature [9] in terms of percentage strength increase, but differs in terms of the quantity of mound soil causing the increment. This difference may be attributable to difference in the source of MS. Table 13 showed that at this optimum combination, standard slump of 24mm was observed. This amounted to an increase of 36.92% in workability. CONCLUSION The paper concludes that mound soil can be used in construction as an additive in concrete but should not exceed 15%. MSC has the advantage of high compressive strength and good workability. 994

6 REFFRENCES Denis, H Carbonation Induced Corrosion. Conc. Magazine Vol. 34, No 6, pp Fox, T. A Use of Coarse Aggregate in Controlled Low Strength Materials. Transportation Research Record, No Felix, F. U., Alu, O. C. and Suleiman, J Mound Soil as a Construction Material. Journal of Materials in Civil Engineering, ASCE, Vol. 12, No. 3, pp Hook, W. and Clem, D. A Innovative Uses of Controlled Low Strength Material (CLSM) in Colorado, The Design and Application of Controlled Low-Strength Materials (Flowable Fill), ASTM STP West Conshohocken, PA, American Society for Testing Materials. Ohlheiser, T. R. 1998). Utilization of Recycled Glass as Aggregate in Controlled Low-Strength Material (CLSM), Testing Soil Mixed with Waste or Recycled Materials. ASTM STP 1275, West Conshohocken, PA. Orie, O.U. and Osadebe, N. N Optimization of the Strength of Five-Component- Concrete Mix using Scheffe s Theory A case Study of Mound Soil Concrete. Journal of the Nigerian Association of Mathematical Physics, Vol. 14, pp Pons, F., Landwermeyer, J. S. and Kerns, L Development of Engineering Properties for Regular and Quick-Set Flowable Fill. The Design and Application of Controlled Low-Strength Materials (Flowable Fill), ASTM STP West Conshohocken, PA, American Society for Testing Materials. Snethen, D. R. and Benson, J. M Construction of CLSM Approach Embankment to Minimize the Bump at the end of the Bridge. The Design and Application of Controlled Low-Strength Materials (Flowable Fill), ASTM STP West Conshohocken, PA, American Society for Testing Materials. Sullivan, R. W Boston Harbor Tunnel Project Utilizes CLSM. Concrete International, Vol. 19, No