20120130407004 2-3-4-5


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20120130407004 2-3-4-5

  1. 1. International Journal of Advanced JOURNAL OF ADVANCED RESEARCH ISSN 0976 – INTERNATIONAL Research in Engineering and Technology (IJARET), IN 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME ENGINEERING AND TECHNOLOGY (IJARET) ISSN 0976 - 6480 (Print) ISSN 0976 - 6499 (Online) Volume 4, Issue 7, November-December 2013, pp. 25-37 © IAEME: www.iaeme.com/ijaret.asp Journal Impact Factor (2013): 5.8376 (Calculated by GISI) www.jifactor.com IJARET ©IAEME STUDIES ON RICE HUSK ASH CEMENT MORTAR 1 Er. S.THIROUGNANAME, 2 Dr. T.SUNDARARAJAN 1 M.Tech., MIE., MISTE., FIAH., MIWWA., AMISE., MITArb., Assistant Engineer, Public works Department, Puducherry, India 2 Professor, Department of Civil Engineering, Pondicherry Engineering College, Puducherry, India ABSTRACT Rice husk which is an agricultural by–product is abundantly available all over the world. Most of the rice husk, which is obtained by milling paddy, is going as a waste materials even though some quantity is used as bedding material, fuel in boilers brick kilns etc., A detailed experimental investigation conducted on the strength of Rice Husk Ash (RHA) mortar of various proportions and various replacement levels have shown that mortar with superior properties can be made. Keywords: Rice Husk, Mortar, Rice Husk Ash (RHA), Ordinary Cement (OPC). ASHMOH. INTRODUCTION NEED FOR AN ALTERNATIVE BINDER Most important and highly expensive building material is Ordinary Cement (OPC). The use of OPC attracted every one in the construction industry and its application in steadily increasing when compared to other material used in those days due to: i) Rapid changes in the technology in the manufacture of cement, ii) Its early gain of strength and, iii) Progressive improvement in strength in the presence of moisture leading to an impervious mass. But the product gives considerable shrinkage, creep etc, during and after setting and hardening. Even after extensive utilization of OPC till date, the durability of OPC has been still being investigated and it is questionable. With the present level of OPC production, it is not possible to meet the dewelling needs of the country and also for pavement of roads, bridges, canal works etc. The neat strength of OPC is diluted from 60-80 MPa to a characteristic strength in the range of 15-50 MPa by appropriate changes in the mix design of concrete. M15 grade concrete is used in general construction works, as 25
  2. 2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME this characteristic strength is sufficient for most of the building elements. From above, it is clearly seen that a high strength binder like OPC is not needed for most of the general works and hence it can be substituted partially or fully by producing a binder from waste materials at lesser cost but with a desirable degree of strength and durability. The answer to the above question has been realized in the form of Rice Husk Ash (RHA), which has been proved to be a successful replacement up to 50% of OPC [1]. POTENTIAL OF RICE HUSK ASH AS A BINDER / POZZOLANIC MATERIAL Rice Husk which is an agricultural by-product is abundantly available all over the world, more so, in the countries like India, where it is a staple food. It is estimated that 1000Kg of Paddy will yield 200 Kg. of husk. Due to this abrasive character, poor nutritive value, very low bulk density and high ash content, a small portion only is used as bedding material, fuel in boilers, brick kilns etc. To overcome the above problems, studies initiated by several investigators on the use of RHA led to its use as a pozzolanic material, in view of its high silica content (say about 90%). LITERATURE REVIEW In this chapter, the work carried out by various investigators (in India and abroad) on the use of RHA for the production of cementitious material; use of RHA as partial replacement of OPC for producing concrete and mortar are reviewed and presented. HYDRAULIC CEMENT FROM RHA As early as in 1974, P.K. Mehta [2] developed a process for making cement from Rice Husk in which the rice husk is burnt under controlled conditions and the ash mixed with hydrated lime. Since the silica in the amorphous RHA is already in a very reactive form, a hydraulic cement can be produced simply by blending or by intergrinding the RHA with lime. As long as lime and silica are present in active state in an anhydrous material, the cementing property can be obtained in aqueous environments through formation of the calcium silicate hydrates. In some experiments, blends of Portland Cement with RHA yielded good quality hydraulic cements. One unique characteristic of RHA cement is a permanent black colour which is useful in making black concrete for glare-free pavements or for architectural applications. The second unique characteristic of RHA cements. is the excellent resistance of the materials to acidic environments. Upon hydration of these cements, none of the lime would be present in the form of free Ca(OH)2. The products of hydration consists of calcium silicate hydrates and silica gel and therefore more resistant to acid attack. CEMENTITI OUS BINDER FROM WASTE LIME SLUDGE AND RICE HUSK CBRI, India has evolved a cementitious binder from waste lime sludge and rice husk. The powder form of waste lime sludge and rice husk are dry mixed together roughly in equal amounts by weight and the required quantity of water added to dry mix, for making cakes. After drying them, they are fired in open with a grating base or in a trench. The fired material are then ground in a ball mill to achieve sufficient fineness. The binder thus obtained had inherent characteristics of lime based compositions. Some of the important properties of the above types of binders are given in Table 1. 26
  3. 3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME Table 1: Properties of the Binder produced from Waste Lime and Rice Husk S. No. Property Value 1. Bulk density (Kg/m3) 360(on firing) 700(on grinding) 2. Setting times Initial (min) Final (min) 1:1.5 (Binder:sand) 1:20 (BInder:sand) 3. 4. 60 - 90 480 – 600 71%(flow) 60%(flow) Water retention Soundless (Le-Chatlier) (mm) 1.50 Note: Water retention is tested as per IS: 2250, ‘Code of practice for preparation and use of masonry mortars’. The crushing strength values of the above binder (tested as per IS: 712-1973, Specification for building lime) using one part of binder and three parts of standard sand and using three types of sludge, namely, sugar sludge, carbide sludge and paper sludge satisfied the requirement of class-A lime i.e. eminently hydraulic (14 and 28 days stipulating strength being 17.5 kg/cm2 and 28.0 kg/cm 2). The above binder was recommended for plastering and can be used as plain cement concrete (PCC) works in foundations, floors, using conventional aggregates for use in precast hollow or solid blocks for light loading purpose, for stabilizing soil; bricks with sand under pressure using semi-dry mix. In spite of the above indicated uses, it did not gain popularity due to quick-setting nature of the cementitious material and the process was found to be cumbersome and not suitable for large-scale commercial production. CEMENT FROM RICE HUSK ASH At I.I.T., Kanpur, two alternate routes were developed for making cement from RHA namely i)ASHMENT process and ii) ASHMOH process. In the ASHMENT process, RHA is ground alone in a ball mill and mixed with Portland cement in a specified weight ratio, in the range of 3/2 to ½ and the resulting blend called as ASHMENT cement. However, in the planted ASHMOH process, RHA, lime and an additive are ground together in a ball mill to form ‘ASHMOH cement’. The same plant can employ ‘ASHMOH’and or ‘ASHMENT’ technologies without any modifications. RAW MATERIALS, PROPERTIES AND APPLICATIONS OF ASHMOH CEMENT Raw Materials RHA obtained from the combustion process of rice husk as fuel or rice husk heaps burnt in open fields, hydrated lime containing atleast 85% CaO content; OPC as an additive (8 – 10%) to hasten the setting time, are the raw materials required (i.e. 64%; 27%; 9% - RHA; hydrated lime; additive- OPC) ASHMOH cement obtained by the process had the properties as given in Table 2. 27
  4. 4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME Sl No. 1 2 3 4 Table 2: Properties of ASHMOH Cement Property Setting times Initial (min) Final (hrs) 60 - 90 6 -7 Compressive Strength (ASHMOH : sand = 1:3 and W/B = 0.475 – 0.5) at 3 days ( Kg/cm2) 7 days ( Kg/cm2) 28 days ( Kg/cm2) 110 – 150 140 – 180 220 – 280 Compressive Strength of 1:2:4 ASHMOH concrete W/c = 0.55-0.65) ( Kg/cm2) 140 – 190 Bulk density ( Kg/cm2) 700 - 750 Value Note: The loose bulk density of ASHMOH is about 50% of that OPC and hence when preparing mixes by volume, 1.8 to 2.0 times the required volume of ASHMOH cement is taken, to maintain the weight ratios constant. Applications ASHMOH cement is not recommended for reinforced or prestressed concrete load bearing structures, such as roofs, lintels etc. It is eminently suitable for non-critical routine applications such as masonry work, sand-cement bricks and blocks, soil stabilization, village roads; water tanks, canal lining, water conduits; foundation concrete etc., but not for RCC works. ASHMOH is compatible with OPC in all proportions. A mixture of the two, containing more than 30% OPC, is for all intents and purposes indistinguishable from conventional cement (OPC) Inspite of the certain properties claimed by the investigators at IIT Kanpur, tests conducted at Annamalai University (2) indicated that the initial setting time is about 30 minutes and the strength at 28 days of normal curing 120 kg/cm2 only, which was normally expected of a binder, such as indicated above. CEMENT FROM RICE HUSK, CLAY AND HYDRATED LIME A process has been developed to make high quality pozzolanic materials from rice husk and clay. The pozzalonic which mixes with lime gives a very good cementitous material and when blended with Portland Cement gives a Portland Pozzolana cement. To make lime-pozzolana cement, the finely ground Pozzolana as obtained is intimately mixed in the dry hydrated line in the ratio of 2:1 (by volume). This may be mixed insitu at the construction site or during grinding of the pozzolana. Following are the various properties of the rice husk clay pozzolana, obtained by the above process. Loss of ignition Specific gravity Lime reactivity (IS 1727 – 1967) Lime pozzolana mortar - 1.5% 2.34 64 to 106 ( Kg/cm2) 44 to 72 ( Kg/cm2) 28
  5. 5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME The strength properties of Rice Husk Clay pozzolana are given in the Table 3. Table 3: Strength Properties of Rice Husk Clay Pozzolana Compressive Strength Composition ( Kg/cm2) Water Retention 7 days 28 days 1:6 (cement : sand) 1:2:6(lime:Pozzolana:sand) 1:2:9(lime:Pozzolana:sand) 12-20 24.4 13 20-30 45.2 22.5 30 72 67 The lime pozzolana has superior properties and chaper in cost and can replace OPC in normal construction works as a mortar for masonry and for plastering. However, it should not be used for any RCC work. RESEARCH CARRIED OUT AT ANNAMALAI UNIVERSITY ON CEMENITIOUS MATERIALS FROM RICE HUSK During 1979-82, research work on the production of paddy husk cement from paddy husk and lime was carried out in different stages at Annamalai University (2,3) Systematic experimental studies were conducted on the type of furnace required to obtain good burnt clinkers of rice husk and lime by open burning, the effect of various ratios of the blend of RHA and lime on the compressive strength and on the effect of type of curing (normal and stem curing) on the strength attainment and various strength characteristics. Gypsum was used as an additive (5% , 10% and 15%) to control the setting times of the cementitious material and to study its effect on the strength of cement. From the extensive test results obtained it has been concluded that the i. Compressive strength of rice husk is the same both for normal and steam curing at 28 days and it is the order of 90 ( Kg/cm2) ii. The adhesive strength of the above mortar (1:4, by wt) is about 50% of that of conventional cement. iii. It is found that the rice husk cement has good setting properties when compared to that of OPC. iv. The bulk density of rice husk cement is only 790 ( Kg/m3) which is about 50% of the bulk density of OPC. Thus, the rice husk cement mortar ratio of 1:1:5 (volume) is the same as 1:3 by weight. The above mortar can be recommended for wall plastering and floor etc., v. The compressive strength of brick masonry blocks plastered with rice husk cement on all the sides was found to be equal to that of the strength of OPC blocks and, vi. Stem curing produces a further rate of increase in hardening of cement and that the optimum period of stem curing is 7 hours. They have also suggested further studies on the effect of stem curing pressure (I,e, at low, medium and high) on the various properties. 29
  6. 6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME STUDIES ON RHA – CEMENT CONCRETE AND MORTAR Studies in Taiwan Taiwan produces abundant quantity of rice husk containing primarily silica, rice husk possesses reactive characteristics after burning and hence, large potential for use in concrete than for soil stabilization. The reactive of RHA is dependent on both its origin and its treatment. The effect of RHA on the microstructure, shrinkage, porosity and strength development characteristics of the cement paste were studied by Hwang and Wu (4). They investigated the effect of temperature of burning rice husk on the reactivity of the resulting RHA, which was quantitatively and qualitatively investigated by means of X-ray diffraction and EDAX. In addition, the effect of RHA on cement properties, was investigated covering the aspects such as workability, bleeding, setting times, shrinkage, absorption, compressive strength and heat of evolution in the paste during hydration. Moreover, ignition loss, optical microscopy, SEM and MIP investigations were employed to analyze both hydration mechanisms and micro-structure. From the above studies they have concluded that i. Factors such as, heating rate, burning period, ambient furnace conditions will affect the quality of ash, ii. At a higher burning temperature of 700 C, rice husk forms ash primarily composed of SiO2 Higher temperature do no yield greater quantities of SiO2 iii. The heat of hydration varies inversely with the water-cement ratio (w/c) regardless of whether or not the system contains RHA. iv. The amount of bleeding is inversely proportional to the RHA content in the paste and v. The water retaining effect of RHA and the increased quantity of C-S-H get generated by the ash that fills the space previously occupied by free water both influence the strength and physical properties. Cement paste containing RHA at a higher w/c (0.52 to 0.54), develops higher ultimate strength than that without ash after 60 days, although their early strengths are similar. Studies in Japan Sugita and others (5) studied i) the temperature effect on the incineration of rice husk to obtain large amounts of non-crystaline ash, ii) pozzolanic reactivity of RHA using the Ca(OH)2 solution in electric conductivity in relation to the X-ray diffraction method; iii) pulverizing property of RHA iv) the relationship between the compressive strength of mortar with RHA and conductivity data v) the porosity changes and drying shrinkage of mortar with RHA and vi) resistance to acid attack and carbonation of mortar containing RHA. From the above studies they concluded that i. Lower combustion temperature over the flash point and shorter combustion periods, the higher the amount of non-crystalline RHA. ii. Higher the non-crystalline form of RHA, lower the energy required to pulverize it. iii. Variation in electric conductivity indicates the amount of non-crystalline RHA present in the sample. iv. RHA obtained in electric hearth below 600°C and pulverized for 80 minutes, had a higher pozzolanic activity than other pozzolanic materials, such as fly ash, v. Drying shrinkage of mortar increased with the addition of RHA, which may be due to the increase in fine pores in the mortar. 30
  7. 7. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME vi. There is improvement in the resistance to acid attack by using highly non-crystallized RHA. vii. Depth of neutralisation of mortar with RHA was estimated to be similar to that of controlled mortar (without RHA) and, viii. Freeze-thaw resistance of mortar with RHA was similarly to that of controlled mortar, which depends on the W/B and the amount of RHA. Studies in Turkey Mazlum and Vyan(6) studied the temperature effect of incinerating rice husk in furnaces at 400° C and 500° C for 1, 5 hours to obtain silica of amorphous state by sudden cooling. They studied the effect of environmental sulphate attack (Na2SO410H2O) on the flexural and compressive strength of mortars after 4,8, 12 weeks of exposure in the above medium, for RHA contents in cement ranging between 10% - 30% (by weight) at a constant W/B = 0.57 and using a super plasticiser (naphthalene formaldehyde). The specimens were exposed to the medium only after 28 days of normal curing and the results were compared with that of controlled mortar. From the above studies, they concluded that i) the flexural and compressive strengths of ash mortars (cured in water) are greater than those of controlled mortars ii) the flexural strength of ash mortars exposed to Na2SO4 medium have greater values than that of controlled mortars and ash mortars kept under normal curing and iii) that RHA is an active pozzolana and it can be used in sulphate environments, successfully. Studies on RHA Cement Concrete in India Seshagiri Rao and others (7) carried out detailed investigations on RHA cement concretes to evaluate its use as a structural material (i.e. for RCC applications and as a pavement material). The investigations were carried out to find the influence of a) fineness of ash; b) water/cement ratio; c) Cement-RHA content and; d) strength and durability of RHA concretes. Compressive strength, flexural strength (on PCC beams), flexural strength of RCC beams and slabs were studied. In order to study the durability, tests on permeability, abrasion resistance and resistance to dilute acids (5% HCI, H2SO4 and Acetic acid; 30 – 90 days of immersion, change in weight) were determined for RHA levels of 0-40%. From the above studied they have concluded that i. ii. iii. iv. v. vi. RHA fineness of 16,000 cm2/gm is optimum Upto 30% cement can be replaced by RHA for M15 and M20 grades. Flexural strengths are comparable with reference concretes. There is reduction in permeability. There is improved abrasion resistance and to acid attack and, RHA reinforced concretes are in no way inferior to conventional reinforced concretes. However, the above studies were not directed in evaluating RHA cement concrete as a pavement material, excepting the abrasion resistance test, i.e. whether it conforms to pavement quality concrete (PQC) has not be evaluated. SCOPE OF THE PRESENT STUDY RHA-Cement mortar strength for three mix proportions, namely 1:4, 1:5 and 1:6 and at 10%, 20% and 30% replacement of cement by RHA have studied and results presented. The suitability or otherwise of RHA-Cement mortar for masonry works has also been ascertained. 31
  8. 8. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME EXPERIMENTAL INVESTIGATIONS Experimental investigations to study the strength the of RHA cement mortar were conducted. PROPERTIES OF MATERIALS USED Cement, fine aggregate (FA) (sand conforming to Zone-II gradation based on IS:383-1970); Rice Husk Ash are the various materials used in this study. The basic properties of the above materials are given below. Cement 43 grade OPC (ACC brand) is used as the primary binder. The required quantity was procured a single batch, stored and used throughout the whole programme. The physical properties of cement obtained and used are given in Table 3.1. Table 3.1: Physical Properties of OPC Property Sl.No. Results 1 Normal Consistency 29% 2 Initial setting time 110 min 3 Final setting time 160 min 4 Fineness (Blaines air permeability) Fineness (by dry sieving) 5 Specific gravity 6 7 Soundness value (Le-Chatlier 3.15 Compressive strength (*) 3days 7 days 28 days Note : (*) 285 m2/kg 9% 2.5mm 20.87 N/mm2 25.88 N/mm2 36.02 N/mm2 Standard sand is used Fine Aggregate (FA) Sand conforming to grading Zone-II of IS: 383 -1970 is used as fine aggregate (FA). Its properties are given in Table 3.2. Sl.No. Table 3.2: Properties of Fine Aggregate Property Results 1 Specific gravity 2.60 2 Water absorption 0.55% 3 Fineness modulus 2506 32
  9. 9. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME Rice Husk Ash (RHA) Paddy husk obtained from PAPSCO, Puducherry is used to prepare ash. Only a mixed variety of paddy husk could be obtained from the above source. Heaps of 25-30. Kg was burnt in open yard for over 24 hours at a time and the ash obtained was collected in clean bags. Initial dry sieving indicated the presence of large quantities of particles higher than cement size and hence, it was decided to pulverize the ash so that cement sized particles could be obtained i.e. 90% of particles passing through 90 micron sieve. The above process was done in M/s. Kumar Minerals Mettupalayam Industrial Estate, Puducherry. Only such ash is used in the present study after again dry sieving them to ascertain its fineness. Ash obtained by the above process was used for the partial replacement of OPC, the replacement levels ranging 10 – 30% (by weight). The various chemicals properties of RHA are determined in the chemical testing and analytical laboratory Guindy, Chennai- 32 and the physical properties by standard laboratory methods. The above results are given Table 3.3. Sl.No. 1 2 3 4 5 6 7 Sl.No. 1 2 3 4 5 Table 3.3: Chemical Properties of RHA Property Moisture PH of 5% solution Electrical conductivity (EC) of 5% solution in milli mohz Total Carbon © Total Potassium as K2O Silicon as Si Total Phosphorus as P2O5 Value 0.67% 8.70 0.55 29.68% 0.89% 35.65% 0.49% Table 3.4: Physical Properties of RHA Property Results Normal Consistency 30% Fineness (before pulverizing) Dry sieving 77% (wt. retained on 75 µ) Fineness (before pulverizing) Dry sieving 12.5% (wt retained on 75 µ) Wet Sieving 18.2%(Wt. retained on 75 µ) 17.9% (wt. retained on 45 µ) Specific gravity Compressive strength (MPa) on mortar Cubes 1:3 using standard sand ) at 3days 7 days 28 days 2.14 8.5 / 5.1/4.00 10.9 / 6.3 / 5.10 17.7 /16.7 /16.10 Note: The two values of compressive strength correspond to 10%, 20% and 30% replacement levels of RHA in OPC, in that order of occurrence, in the above table 3.4. Water Ordinary potable tap water available in laboratory was used for making mortar and concrete and for curing purposes. 33
  10. 10. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME TESTS ON WET RHA – CEMENT MORTAR Normal consistency of RHA-Cement mortar, setting times (initial and final) were carried out on wet mortar. Normal Consistency and Setting Times The quantity of water required to produce a cement paste of standard consistency at various replacement levels of OPC by 10, 20% and 30% by RHA and their corresponding setting times were determined by standard testing procedures. The above results are given in Table 3.5. Sl. No. Table 3.5: Consistency and Setting Times of RHA-Cement Replacement of RHA levels Description 10% 20% 30% 1 Normal Consistency (%) 39 45 51 2 Initial setting time (min) 150 90 54 3 Final Setting time (min) 195 185 110 Tests on RHA – OPC Mortar Three different mix proportions, namely, 1:4, 1:5 and 1:6 (by volume) are considered and the cement content in each mix proportion was replaced by 10%, 20% and 30% of RHA. The above mix proportions were selected based on the normal range of proportions adopted in practice for various masonry works. The conventional mix proportions were converted into equivalent mix proportions (by weight considering bulk density) and used in the actual mixing of mortar and hence, in determining the flow value and the compressive strength of RHA – OPC mortars. Water required to yield a mortar with 100% flow was determined in accordance with IS:4031 and casting cubes of size 70.6 x 70.6 mm were cast. The above cubes were tested after 28 days of normal immersion curing for their compressive strength in the compression testing machine adopting standard testing procedures. RESULTS AND DISCUSSION Results of various tests conducted on RHA cement mortar preparation 1:4, 1:5, and 1:6 (by volume) consisting of partial in the range of 10 – 30% are presented. The compressive strength (at 28 days) test results of various mix proportions (1:4, 1:.5 and 1:6 volume and with the required water for 100% flow) are given in Table 4.1. From the above test results following inferences are drawn: i. Compressive strength of RHA cement mortar (at 28 days) is always less than that of conventional (cement mortar for all the three mix proportions and at all replacement levels of RHA. ii. Maximum compressive strength of the mortar is obtained at the replacement level of 20% RHA, for all mix proportions, considered in this study. iii. Comparing the compressive strength obtained for RHA cement mortar with the minimum strength requirement of masonry mortar as given in IS:2250 – 1981, for corresponding mix proportions, the strength of RHA cement mortar is less than the specified value and 34
  11. 11. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME iv. Therefore, in order to use such mortars, the desired minimum compressive strength of masonry mortars, as stipulated in the IS code for various uses, are compared with the actual strength of RHA – cement mortar. It is found that RHA - cement mortar of 1:4 (up to RHA replacement of 30%) equals the strength of CM 1:5, for masonry mortar. Similarly, RHA cement mortar of 1:5 and 1:6 (up to RHA replacement level of 30%) equal the compressive strength of 1:6 for masonry mortar. Hence, the mortar can be used for bedding joints i.e. for regular masonry work. Table 4.1: Water Requirement for 100% Flow and Compressive Strength of Various Mortar (at 28 days) Sl.No Mix Proportion by volume and Water for 100% Comp.strength at 28 RHA replacement flow (%) days (N/mm2) A)1:4 (by vol 1:4167 – by wt) 1 0% 16.50 11.04 2 10% 20.20 5.60 3 20% 20.30 8.47 4 30% 24.10 7.00 B)1:5 (by vol. 1:5208 – by wt) 5 0% 17.10 9.50 6 10% 21.90 3.00 7 20% 23.50 4.60 8 30% 25.50 4.13 C)1:6 (by vol. 1:6250 – by wt) 9 0% 17.70 5.22 10 10% 22.70 2.20 11 20% 24.90 3.95 12 30% 26.10 3.50 35
  12. 12. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME CONCLUSIONS Based on the extensive experimental investigation carried out on RHA –Cement Mortar following are the conclusions drawn. i. Water required for 100% flow in RHA-Cement Mortar is more than the water required for conventional mortar for all the three mix proportions considered in this study, namely 1:4, 1:5 and 1:6 for all replacement levels of RHA. ii. 1:4 RHA-Cement Mortar attains the comparable compressive strength as that of 1:5CM (i.e. grade MM7.5 as prescribed in IS: 2250 – 1981) Hence, the above mortar can be used for masonry in buildings subject to vibration of machinery and also bedding joints in masonry with large concrete blocks. The above observation is valid up to 30% of RHA in the above mortar. iii. Similarly 1:5 and 1:6 RHA-Cement mortar attains the comparable compressive strength of conventional mortar (i.e. CM) of mix proportion 1:6 (i.e. grade MM 3, as prescribed in IS:2250 – 1987). Hence, the above mortar can be used with confidence in masonry works including bedding joints. REFERENCES 1) Seshagiri Rao M.V. Saibaba Reddy E. Ramamohan Rao K. (1996) ‘Rice Husk Ask Cement Concrete’ Proceeding of National Seminar on Alternate Construction Materials in Civil Engineering held at REC Hamipur December 10-11, 1996, PP 321 – 330. 2) Lakshman S. (1980) Investigations on the Properties of Paddy Husk Cement, M.E. Thesis submitted to the Annamalai University, Department of Applied Mechanics and Structural Engineering PP.62 3) Subramanian C. (1982) ‘Further study on Cement from Paddy Husk’ M.E. Thesis submitted to the Annamalai University, Department of Applied Mechanics and Structural Engineering PP.55 4) Hwang C.L. Wu D.S. (1989) ‘Properties of Cement paste containing Rice Husk Ash’ Proceedings of the Third International Conference on Natural Pozzolans in Concrete Trondheim, Norway, SP-114, published by ACI, Malhotra V.M. (Ed). Volume – I, PP. 733 -762. 5) Sugita S, Shoya M. and Tokuda H. (1992) ‘Evaluation of Pozzolanic Activity of Rice Husk Ask’ Proceedings of the Fourth International Conference on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete, Istanbul, Turkey, SP – 132, published by ACI, Malhotra V.M. (Ed), Volume I, PP.495 – 512. 6) Mazlum F., and Uyan M. (1992) ‘Strength of Mortar made with Cement Containing Rice Husk Ash and Cured in Sodium Sulphate Solution, Proceedings of (as in 5 above), PP. 513 – 532. 7) Seshagiri Rao M.v. Prasada Rao A. (1997) ‘Rice Husk Ash Cement Concrete for Rigid Pavements’ Indian High ways, Volume 25, No.9, PP 13 – 22. 8) Mohammad Qamruddin and Prof.L.G.Kalurkar, “Effect of Unprocessed Rice Husk Ash as a Cementitious Material in Concrete(A Comparison with Silica Fume)”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 2, 2013, pp. 240 - 246, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. 9) Raju Sathish Kumar, Janardhana Maganti and Darga Kumar Nandyala, “Rice Husk Ash Stabilized Compressed Earth Block-A Sustainable Construction Building Material – A Review”, International Journal of Civil Engineering & Technology (IJCIET), Volume 3, Issue 1, 2012, pp. 1 - 14, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. 36
  13. 13. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 7, November – December (2013), © IAEME BIBLIOGRAPHY 1. 2. 3. SP:23 - 1982 IS:269 - 1976 IS:383 - 1970 4. 5. 6. 7. 8. 9. 10. 11. IS:456 IS:516 IS:1199 IS:1727 IS:2250 IS:3812 IS:4031 IS:5816 - 1978 - 1959 - 1959 - 1967 - 1981 - 1981 - 1988 - 1970 Hand Book on Concrete Mix. Specification for Ordinary and Low Heat Portland Cement. Specification for Coarse and Fine Aggregate from Natural Sources for Concrete. Code of Practice for Plain and Reinforced Concrete. Methods of Test for Strength of Concrete. Methods of Sampling and Analysis of Concrete. Methods of Test for Pozzolanic Materials. Code of Practice for preparing and Use for Masonry Mortars’. Specification for Fly Ash for use as Pozzolana and Admixture. Methods of Physical test for Hydraulic Cement (Part VII). Methods of Test for Splitting Tensile Strength of Concrete Cylinders. AUTHOR’S DETAIL Er. S.THIROUGNANAME, M.Tech., MIE., MISTE., FIAH., MIWWA., AMISE., MITArb., Assistant Engineer, Public works Department, Puducherry. 37