Research Article Volume 6 Issue No. 9

Transcription

1 ISSN XXXX XXXX 06 IJESC Research Article Volume 6 Issue No. 9 Replacement of Natural Sand with Robo/Artificial Sand in Specified Concrete Mix K. Srinivas Reddy Assistant Professor Department of Civil Engineering Teegala Krishna Reddy Engineering College, Hyderabad, Telangana, India Abstract: Now a day the construction industry in the India is facing one of the major problems that is natural fine aggregate. And court awarded that totally band on excavation of fine aggregate from river because they affect on environment and changing the river direction Cement, sand and aggregate are basic needs for any construction industry. Sand is a prime material used for preparation of mortar and concrete and which plays a major role in mix design. Now a day s erosion of rivers and considering environmenta l issues, there is a scarcity of river sand. The non-availability or shortage of river sand will affect the construction industry; hence there is a need to find the new alternative material to replace the river sand, such that excess river erosion and harm to environment is prevented. Many researchers are finding different materials to replace sand and one of the major materials is quarry stone dust (Artificial/Robo/M -SAND). Using different proportion of this robo sand along with sand the required concrete mix can be obtained. Replacement of natural fine aggregate with artificial fine aggregate by 0%, 40% 60% and also finding the compressive Strength of that concrete cube This Project presents a review of the different alternatives to natural sand in preparation of concrete. The project emphasize on the physical and mechanical properties and aspect on concrete Key words: Artificial/Robo/M SAND, Natural sand, cement, concrete, course aggregate, Physical Properties, Mechanical Properties, Curing,, Research significance I. EXPERIMENTAL PROGRAM The main objective of this experimentation is to find out the effect of replacement of natural sand by manufactured sand with 0%, 40% and 60% on hardened properties of cement concrete. The experimental work includes the casting, curing and testing of specimens. Concrete mix is prepared with proportion of :.4:.9 with water cement ratio of.44 and 0.5 respectively. Three trials are carried out for each water cement ratio and concrete mix proportion, where Mix is the reference mix with 0% manufactured sand, Mix is with 40% replacement of natural sand by manufactured sand and Mix is with 60% manufactured sand. All of the experiments are performed in normal room temperature. The mortar ingredients namely cement, fine aggregate and coarse aggregate first mixed in dry state. Manufactured sand is used as a partial replacement to the natural sand then calculated amount of water is added and mix it thoroughly to get a homogeneous mix. Mortar is poured in the moulds layer by layer and compact thoroughly. Cubes are used for compressive test having size 50 mm (5.9 in) x50 mm (5.9 in) x 50 mm (5.9 in) that are cured in water for 7 & 8 days and tested at 7 & 8 day s on Universal testing Machine (UTM). II. INTRODUCTION Cement, sand and aggregate are essential needs for any construction industry. Sand is a major material used for preparation of mortar and concrete and plays a most important role in mix design. In general consumption of natural sand is high, due to the large use of concrete and mortar. Hence the demand of natural sand is very high in developing countries to satisfy the rapid infrastructure growth. The developing country like India facing shortage of good quality natural sand and particularly in India, natural sand deposits are being used up and causing serious threat to environment as well as the society. Rapid extraction of sand from river bed causing so many problems like losing water retaining soil strata, deepening of the river beds and causing bank slides, loss of vegetation on the bank of rivers, disturbs the aquatic life as well as disturbs agriculture due to lowering the water table in the well etc are some of the examples. The heavy-exploitation of river sand for construction purposes in Sri Lanka has led to various harmful problems. The alternate material to river sand Various Experiments considered:-. Specific gravity of sand.. Specific gravity of Cement. Specific gravity of robo sand 4. Specific gravity of course aggregate 5. Slump cone test on fresh concrete 6. Sieve analysis 7. Compression testing on concrete cubes (50x50x50 mm) International Journal of Engineering Science and Computing, September

2 Copper slag.washed Bottom Ash.4 Coarse Aggregate: Crushed stone aggregates of 0mm size obtained from local quarry site were used for the experimentation. The fineness modulus of coarse aggregates was found to be 6.with a specific gravity of.76 the water absorption and moisture content values obtained for the sand used was found to be.5% and 0.5% respectively. IV. ROBO SAND AND PROPERTIES The artificial/robo sand produced by proper machines can be a better substitute to river sand. The sand must be of proper gradation (it should have particles from 50 microns to 4.75 mm in proper proportion). Robo sand is a purified form of quarry dust with is excreted from manufacturing of coarse aggregate. Which mostly in the form of chips. These baby chips are crushed to the specified size of mm as required. In fact both natural sand and robo sand look similar. They don t differ in many properties like water absorption. But now there they started manufacturing separate for sand Construction and Demolition waste 4 Quarry Dust Fig. Indicating the different alternative materials III. MATERIALS US ED: The properties of various materials used in making the concrete (M5) are discussed in the following sections.. Cement Ordinary Portland cement of 4 grades satisfying all the requirements of IS was used in making the concrete slab panels and cubes in the experimental work. Physical properties Values for OPC used Standard consistency.5% Sp gravity.5 Initial setting time >0 min s Final setting time <600 min s TABLE Typical properties of Cement 4 grade IS General Requirements of Manufactured Sand. All the sand particles should have higher crushing.. The surface texture of the particles should be smooth.. The edges of the particles should be grounded. 4. The ratio of fines below 600 microns in sand should not be less than 0%. 5. There should not be any organic impurities 6. Silt in sand should not be more than %, for crushed sand. 7. In manufactured sand the permissible limit of fines below 75 microns shall not exceed 5%.. Natural (River) Sand: The natural sand having fineness modulus of.78 and conforming to zone II as per IS: was used for the experimentation after washing it with clean water. The specific gravity of this natural sand was found to be.55. The water absorption and moisture content values obtained for the sand used was found to be 6% and.0% respectively.. Artificial sand (Crushed sand): The crushed sand having fineness modulus of.8 and conforming to zone II as per IS: was used for the experimentation after washing it with clean water. The specific gravity of this artificial sand was found to be.66. The water absorption and moisture content values obtained for the sand used was found to be 6.5% and.0% respectively. Properties Natural sand Robo sand Sp gravity Fineness module.78.8 TABLE - Properties of Fine aggregate Fig. MANUFACTING OF ROBO SAND International Journal of Engineering Science and Computing, September

3 Sieve no Percentage of individual fraction retained, by mass Natura l sand Rob o sand Percentage passing, by mass Natura l sand Rob o sand Cumulative Percentage re-tained, by mass Natura l sand 0MM Rob o sand FIG- Typical layout of manufacturing the Artificial/Robo Sand. Properties of Robo sand Organic material NIL content Compatiblity cement with Use with any type of Portland cement and blended cement for various mix designs 4.75M M.6M M.8M M µM µM Setting time Yeild Standard mix design for M0 ::4 per cum Workability W/C Ratio Normal setting time as river Sand Rich mix Cememt-0kg Robo sand- 660kg, 0mm&0mm Course aggregate -0kg Good free water 8 liters per cum. Of concrete 50µM PAN TOTAL Table 5- Fineness modulus and Zone classification Fineness modulus of Natural sand = =.78 Fineness modulus of Robo/Artificial sand =.8 00 =.8 TABLE - properties from all manufacturing units (Robo silica Pvt. Ltd.) V. FINENESS MODULUS AND ZONE CLASSIFICATION The results of aggregate sieve analysis are expressed by a number called Fineness Modulus. Obtained by adding the sum of the cumulative percentages by mass of a sample aggregate retained on each of a specified series of sieves and dividing the sum by 00. The specified sieves are: 50μm (No. 00), 00μm (No. 50), 60μm (No. 0),.8 mm (No. 6),.6 mm (No. 8), 4.75 mm (No. 4), 9.5 mm, 9.0 mm, 7.5 mm, 75 mm, and 50 mm. Graph - Showing fineness modules range for concrete As per the above results the Natural sand and Robo Sand both are of Zone II. And fineness module of Natural sand is.78 and Robo sand is.8 TABLE 4 - IS CLASSIFICATION OF ZONES (I S ) Fig 4 Sieve Analysis of Fine aggregate and Course aggregate International Journal of Engineering Science and Computing, September

4 VI. TYPES OF MIXES 6. Nominal Mixes In the past the specifications for concrete prescribed the proportions of cement, fine and Coarse aggregates. These mixes of fixed cement-aggregate ratio which ensures adequate are termed nominal mixes. These offer simplicity and under normal circumstances, have a margin of above that specified. However, due to the variability of mix ingredients the nominal concrete for a given workability varies widely in. 6. Standard mixes The nominal mixes of fixed cement-aggregate ratio (by volume) vary widely in and may result in under- or over-rich mixes. For this reason, the minimum compressive has been included in many specifications. These mixes are termed standard mixes. IS has designated the concrete mixes into a number of grades as M0, M5, M0 M5, M0, M5 and M40. In this designation the letter M refers to the mix and the number to the specified 8 day cube of mix in N/mm. The mixes of grades M0, M5, M0 an M5 correspond approximately to the mix proportions (::6), (::4), (:.5:) and (::) respectively. 6. Designed Mixes In these mixes the performance of the concrete is specified by the designer but the mix proportions are determined by the producer of concrete, except that the minimum cement content can be laid down. This is most rational approach to the selection of mix proportions with specific materials in mind possessing more or less unique characteristics. The approach results in the production of concrete with the appropriate properties most economically. 6.4 Designated mix: - the concrete producer selects the water cement ratio and the minimum cement content. This approach can be used only if the concrete producer holds a special certificate of product conformity based on product testing and surveillance, coupled with certification of quality assurance. VII. FACTORS AFFECTING THE CHOICE OF MIX PROPORTIONS The various factors affecting the mix design are: 7. It is one of the most important properties of concrete and influences many other describable properties of the hardened concrete. The mean compressive required at a specific age, usually 8 days, determines the nominal watercement ratio of the mix. The other factor affecting the of concrete at a given age and cured at a prescribed temperature is the degree of compaction. According to Abraham s law the of fully compacted concrete is inversely proportional to the water-cement ratio. 7. Workability Workability is a measure of the ease with which a fresh mix of concrete or mortar can be handled and placed. Workability is defined as the amount of useful internal work necessary to produce full compaction. The useful internal work is a physical property of concrete alone and is the work or energy required to overcome the internal friction between the individual particles in the concrete. 7. Durability The durability of concrete is its resistance to the aggressive environmental conditions. High concrete is generally more durable than low concrete. In the situations when the high is not necessary but the conditions of exposure are such that high durability is vital, the durability requirement will determine the water-cement ratio to be used. 7.4 Maximum nominal size of aggregate In general, larger the maximum size of aggregate, smaller is the cement requirement for a particular water-cement ratio, because the workability of concrete increases with increase in maximum size of the aggregate. However, the compressive tends to increase with the decrease in size of aggregate. IS 456:000 and IS 4:980 recommend that the nominal size of the aggregate should be as large as possible. 7.5 Grading and type of aggregate The grading of aggregate influences the mix proportions for a specified workability and water cement ratio. Coarser the grading leaner will be mix which can be used. Very lean mix is not desirable since it does not contain enough finer material to make the concrete cohesive. The type of aggregate influences strongly the aggregate-cement ratio for the desired workability and stipulated water cement ratio. An important feature of a satisfactory aggregate is the uniformity of the grading which can be achieved by mixing different size fractions. 7.6 Quality Control The degree of control can be estimated statistically by the variations in test results. The variation in results from the variations in the properties of the mix ingredients and lack of control of accuracy in batching, mixing, placing, curing and testing. The lower the difference between the mean and minimum s of the mix lower will be the cement-content required. The factor controlling this difference is termed as quality control. 7.7 Mix Proportion designations The common method of expressing the proportions of ingredients of a concrete mix is in the Terms of parts or ratios of cement, fine and coarse aggregates. For e.g., a concrete mix of proportions ::4 means that cement, fine and coarse aggregate are in the ratio ::4 or the mix contains one part of cement, two parts of fine aggregate and four parts of coarse aggregate. The proportions are either by volume or by mass. The water-cement ratio is usually expressed in mass Factors to be considered for mix design The grade designation giving the characteristic requirement of concrete. The type of cement influences the rate of development of compressive of concrete. Maximum nominal size of aggregates to be used in concrete may be as large as possible within the limits prescribed by IS 456:000. The cement content is to be limited from shrinkage, cracking and creep. The workability of concrete for satisfactory placing and compaction is related to the size and shape of section, quantity and spacing of reinforcement and technique used for transportation, placing and compaction. International Journal of Engineering Science and Computing, September

5 VIII. PROCEDURE OF DES IGN MIX 8. MIX DES IGN TES T DATA FOR MATERIALS a) Cement used : OPC 4 grade confirming to IS 8 b) Specific gravity of cement :.5 C) Specific gravity of Coarse aggregate :.74 Fine aggregate :.77 D)Water absorption Coarse aggregate : 0.5 percent Fine aggregate :.0 percent e) Sieve analysis Coarse aggregate : Conforming to Table of IS: 8 Fine aggregate : Conforming to Zone I of IS: 8 TARGET MEAN S TRENGTH FOR MIX PROPORTIONING F t = fck+.65 s Where fck = Target average compressive at 8days, fck= Characteristic compressive at 8 days, s= Standard deviation From Table standard deviation, s = 4 N/mm (IS ) Therefore target = x 4 =.6 N/mm SELECTION OF WATER CEMENT RATIO From Table 5 of IS: , maximum water cement ratio = 0.5 Based on Graph referred water cement ratio adopted is = < 0.45, hence ok Graph Determining W/C Ratio According IS Code SELECTION OF WATER CONTENT From Table-, maximum water content = 8 liters (for 5mm 50mm slump range and for 0 mm aggregates) Estimated water content for normal slump = 8 liters (IS 06). CALCULATION OF CEMENT CONTENT Water cement ratio = 0.44 Cement content = 8/0.44 = 4.6 kg/m =44 kg/m From Table 5 of IS: 456, minimum cement content for severe exposure condition = 44 kg/m > 00 kg/m, hence OK CALCULATION FOR C.A & F.A: Volume of concrete = m Volume of cement = 44 / (.5 X 000) = 0.0 m Volume of water = 8 / ( X 000 ) = 0.80 m Total weight of other materials except coarse aggregate = = 0. m Volume of coarse and fine aggregate = 0. = m Volume of F.A. = X 0. = 0. m (Assuming % by volume of total aggregate) Volume of C.A. = = 0.45 m Therefore weight of F.A. = 0.4 X.55 X 000 = kg/ m Say weight of F.A. = 595 kg/ m Therefore weight of C.A. = 0.45 X.76 X 000 = 96 kg/ m Say weight of C.A. = 96 kg/ m Weight of water =78.54 Water: cement: F.A.: C.A. = 0.44 : :.4 :.88 Sample -: Natural Sand Sample % of Replacement for natural sand by robo sand : 0 % Cement used - Ordinary Portland cement IS :0kg Natural sand Fineness modules.78 Specific Gravity -.55 `:4.kg Robo sand Fineness modules -.8 Specific Gravity.75 : 0kgs Coarse aggregate - Specific Gravity.77 : 8.8Kg Water cement ratio - : 0.44 Date of compaction : 8/7/04 Curing conditions All cubes for cured 7 day and Slump value : 75mm compression load of cube ( compressive 0 N/mm TABLE 6- with 7 days of curing compression load of cube compressive 0.0 N/mm TABLE 7- with 8 days of curing Sample -: 0% Replacement of natural sand by Robo sand% of Replacement for natural sand by robo sand : 0 % Cement used - Ordinary Portland cement IS :0kg Natural sand Fineness modules.78 Specific Gravity -.55 `:.44kg International Journal of Engineering Science and Computing, September

6 Robo sand Fineness modules -.8 Specific Gravity.75 Coarse aggregate - :.86kgs Specific Gravity.77 : 8.8Kg Water cement ratio - : 0.44 Date of compaction : 8/7/04 Curing conditions: All cubes for cured 7 day and Slump value : 68mm compression load of cube compressive N/mm TABLE 8- with 7 days of curing compression load of cube load/sectional area) compressive ,.85 N/mm TABLE 9 - with 8 days of curing Sample -: 40% Replacement of natural sand by Robo sand % of Replacement for natural sand by robo sand : 40 % Cement used - Ordinary Portland cement IS :0kg Natural sand Fineness modules.78 Specific Gravity -.55 `:8.58kgs Robo sand Fineness modules -.8 Specific Gravity.75 : 5.7kgs Coarse aggregate - Specific Gravity.77 : 8.8Kgs Water cement ratio - : 0.44 Date of compaction : 8/7/04 Curing conditions: All cubes for cured 7 day and 8 Slump value : 60mm load compression of cube load/sectional area) compressive 0 N/mm TABLE 0 - with 7 days of curing compression load of cube..88 compressive N/mm TABLE - with 8 days of curing Sample -4: 60% Replacement of natural sand by Robo sand % of Replacement for natural sand by robo sand : 60 % Cement used - Ordinary Portland cement IS :0kg Natural sand Fineness modules.78 Specific Gravity -.55 `:5.7kgs Robo sand Fineness modules -.8 Specific Gravity.75 : 8.58kgs Coarse aggregate - Specific Gravity.77 : 8.8Kgs Water cement ratio - : 0.44 Date of compaction : 8/7/04 Curing conditions : All cubes for cured 7 day and Slump value : 50mm compression load of cube load/sectional area) compressive 6.66 N/mm TABLE - with 7 days of curing International Journal of Engineering Science and Computing, September

7 compression load of cube compressive.77 N/mm TABLE - with 8 days of curing IX. CAS TING & TES TING OF CUBES 9. COMPACTION BY HAND Each layer of the concrete filled in the mould shall be compacted by not less than 5 strokes by tamping bar. The strokes shall be penetrate into the underlying layer and the bottom layer shall be rodded through its depth. Where voids are left by the tamping bar the sides of the mould shall be tapped to close the voids. Fig.7 Pictures while compacting the concrete in moulds (50x50x50mm) 9. COMPACTION BY VIBRATION When compacting by vibration each layer shall be vibrated by means of an electric or pneumatic hammer or vibrator or by means of a suitable vibrating table until the specified condition is attained. 9. CURING Cement sets or cures when mixed with water which causes a series of hydration chemical reactions. The constituents slowly hydrate and crystallize; the interlocking of crystals gives cement its maintaining a high moisture content in cement during curing increases both the speed of curing, and its final. Gypsum is often added to Portland cement to prevent early hardening or flash setting, allowing a longer working time. The time it takes for cement to cure varies Depending on the mixture and environmental conditions initial hardening can occur in as little as 0 mins, while full cure take over a month. Curing is the process in which the concrete protected from loss of moisture and kept within a reasonable temperature range. The casted cubes shall be stored under shed at a place free from the vibration at a temperature 0 C to 0 C for 4 hours covered with wet straw or gunny sacking. The cube shall be removed from the moulds at the end of 4 hours and immersed in clean water at a temperature 4 0 C to 0 0 C till the 7 or 8-days age of testing. The cubes shall be tested in the saturated and surface dry condition. 9.4 of concrete Out of many test applied to the concrete, this is the utmost important which gives an idea about all the characteristics of concrete. By this single test one judge that whether Concreting has been done properly or not. For cube test two types of specimens either cubes of 5 cm X 5 cm X 5 cm or 0cm X 0 cm x 0 cm depending upon the size of aggregate are used. For most of the works cubical moulds of size 5 cm x 5cm x 5 cm are commonly used. 6 Cubes of 50 x 50 x 50 mm size (the nominal size of aggregate does not exceed 8 mm) shall be cast, for 7-days testing and for 8-days testing. ANNEX I (Different pictures of the project) International Journal of Engineering Science and Computing, September

8 Robo Change in Strength sand N/mm with reference mix 0% 0-0% % + 60% TABLE 6 THE COMPRESSIVE STRENGTH FOR 8 DAYS.(N/mm ) Fig 8 THE COMPRESSION TESTING MACHINE Fig 8. Taking readings from the following dial values 9.5 for 7 days After curing of cubes for 7days, the concrete moulds of 50x50x50 mm is tested with a compressive testing machine or universal testing machine. Apply the load gradually without shock and continuously at the rate of 40kg/cm/minute till the specimen fails. The result are shown below:- Robo sand N/mm Change in Strength with reference mix 0% % % % TABLE 5 THE COMPRESSIVE STRENGTH FOR 7 DAYS.(N/mm ) in N/mm % of replacementof natural sand Compressi ve Graph 4 showing the compressive of concrete cured for 7 days and Comparison with reference mix. 9.6 for 8 days After curing of cubes for 8 days, the concrete moulds of 50x50x50 mm is tested with a compressive testing machine or universal testing machine. Apply the load gradually without shock and continuously at the rate of 40kg/cm/minute till the specimen fails. The result are shown below:- in N/mm Graph 5 showing the compressive of concrete cured for 8 days and Comparison with reference mix. 9.7 Comparison Between 7days & 8days of compressive According to the graph and the experimental research the value s is clearly showing the replacement of Natural sand with the Robo sand gives good results regarding compressive. As the w/c ratio is more for Robo sand concrete, the Robo sand absorb more water than the Natural sand. The increased water-cement ratio will gives good workability in Robo sand concrete. As far as we concern the usage of Robo sand in concrete doesn t cause any harm to the concrete structures. Use of this gives a economical concrete as the cost of natural sand is increased due to scarcity of sand. And the Many state government had put restrictions on sand mining in rivers. Which is a environmental issue, so use of Robo sand will not cause any harm to the environment. The use of robo sand can also overcome the scarcity of sand for construction purposes. in N/mm % of replacement of natural sand at the age of 8 days.77 Graph 6 showing the compressive of concrete cured for 7 & 8 days and Comparison with reference mix % of replacement of natural sand Compressiv e of 8 days International Journal of Engineering Science and Computing, September

9 X. CONCLUS IONS The effect of partial replacement of Natural sand by Robo sand on the compressive of cement concrete of grade M5 (:.4:.88 Design mix) with water cement ratio as 0.44 are studied. Results are compared with reference mix of 0% replacement of Natural sand by Robo sand. The compressive of cement concrete with 0%, 40%, 60%replacement of Natural sand by Robo sand reveals higher as compared to reference mix. The overall of concrete linearly increases for 0%,0%, 40%, 60% replacement of Natural sand by Robo sand as compared with reference mix. Robo sand has a potential to provide alternative to Natural sand and helps in maintaining the environment as well as economical balance. Non-availability of natural sand at reasonable cost, forces to search for alternative material. Robo sand qualifies itself as suitable substitute for river sand at reasonable cost. The Robo sand found to have good gradation and better bonding which is comparatively less in natural sand. According to price service ratio the use of robo sand gives effective results, as far as we concern the cost of Robo sand is 0-50% less in market which is good for production of economical concrete. The service of robo sand is also as good enough for as Natural sand concrete. [9]. Marek, C.R. Vulcan Materials Compan y. Importance of Fine Aggregate Shape and Grading on Properties of Concrete. Paper presented at Centre for Aggregate Research, March -4 (995). [0]. Celik, T. and Marar, K. Effects of Crushed Stone Dust on Some Properties of Concrete. Cement and Concrete Research. Vol. 6, No. 7. pp. -0 (996) Future scope of work Replacing natural sand with different % of manufactured sand so that clear variation of can be plotted as well as optimum amount can also be determined. Conducting investigation for M40, M50 and also for high concrete Conducting chloride penetration test and water absorption tests on concrete ensure adequate durability Suitability of manufactured sand must be ascertained for plastering. XI. BIBLIOGRAPHY: []. M.S. Shetty, Text book of concrete technology (theory and practice) S.Chand & Company Ltd []. IS: Recommended Guidelines for Concrete Mix. Bureau of Indian Standards, New Delhi. []. IS: Recommended Guidelines for plain cement Concrete Mix & Reinforced cement concrete. Bureau of Indian Standards, New Delhi. [4]. IS Recommended Guidelines for fine aggregate. Bureau of Indian Standards, New Delhi. [5]. IS 8: Specification for 4 grade ordinary Portland cement, Bureau of Indian Standards, New Delhi. [6]. M.C Nataraja, Fellow of Indian Concrete Institute, Chennai Journals of CIVIL ENGINEERING [7]. Dilip K. Kulkarni. INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING Volume, No, 0. Indian Institute of Technology, Bombay, [8]. Ahmed. A.E. and El-Kourd, A.A. Properties of Concrete Incorporating Natural and Crushed Stone Very Fine Sand. ACI Materials Journal, Vol. 86, No. 4. pp (989). International Journal of Engineering Science and Computing, September