Comparative Study on Concrete with Sawdust as a Partial Replacement for Sand by Conventional and Self-Curing Methods

The environment is threatened by the large-scale mining of natural resources like sand. Therefore, it becomes necessary for us to consider using industrial by-products instead of natural materials in order to save the ecosystem. In this study utilization of saw dust generated by wood industry in concrete has been explored. The purpose of making sawdust concrete is to decrease the waste of sawdust, which could protect the environment in the long run. Concrete is most widely used material in the construction industry, it needs a lot of water for its curing, so it is an urgent need of research to minimize the use of water to cure concrete. Since we identify water shortage is mounting day by day, so vital research should be needed to do the curing without water. So the self-curing method is adopted to minimize the usage of water and it can be adopted where there is acute shortage of water. As the percentage of sawdust content increased from 10% to 20% the compressive strength decreased. Optimum replacement of sand with sawdust has been found to be 10%. By comparison between conventionally and self-cured concrete with respect to its compressive strength and density, compressive strength of conventionally cured concrete gives better result than self-cured concrete. There is reduction in density of sawdust concrete with increase in percentage of sawdust in concrete and also there is decrease in density of self-cured concrete as compared with conventionally cured concrete.

days of curing. For M20 grade concrete, design mix ratio of 1:1.5:3, Compressive strength of Dry Sawdust concrete after 28 days of curing is achieve 80%, 75% and 47% of strength for 10%, 30% and 50% replacement of Dry Sawdust for fine aggregate respectively. After 28 days of curing, the compressive strength for the same grade is 91 percent, 80 percent, and 78 percent for 5 percent, 10 percent, and 15 percent substitution of sawdust ash, respectively. Daniel Yaw Osei et al. in (2017) conducted the experimental studies on the impact of replacing sand with sawdust on the characteristics of concrete. Sawdust was substituted for sand at percentages of 25 percent, 50 percent, 75 percent, and 100 percent by volume in the standard concrete mix of 1:2:4. The corresponding percentage reductions in compressive strength were 57.5 percent, 68.1 percent, 83.7 percent, and 87.3 percent, whereas the percentage reductions in density were 5.96 percent, 12.44 percent, 13.56 percent, and 17.93 percent, respectively. The results showed that as the sawdust replacement percentage increases, both the density and compressive strength of concrete decreased, but that the percentage reduction in compressive strength was greater when sawdust replaced sand. Where concrete strength is a concern, sawdust may be utilized as aggregate.
Abhishek Narayanan et al. (2017) have aimed to form a concrete mixture consisting of sawdust which replaces the fine aggregate. Analysis of sawdust concrete's effects on workability, strength, aggregate adhesion, and other factors are conducted. The weight difference between the original concrete and the sawdust concrete block is also examined after the concrete block has been prepared. The sawdust and concrete are mass-mixed in specific amounts. Then several tests are carried out on both freshly laid concrete and concrete that has already hardened. The analysis's findings indicate that, when sand is partially replaced with sawdust in concrete, workability decreases while the water-to-cement ratio remains constant; the compressive strength of sawdust up to 15% is nearly equivalent to that of sand ratio. Up to 15%, saw dust's compressive strength is nearly identical to that of control mix. In comparison to regular concrete, sawdust concrete is lighter and more cost-effective. The age of curing enhances the compressive strength of concrete cubes and cylinders for all mixes. The findings also suggested that, depending onthe amount of sawdust added to the concrete, both density and compressive strength couldreduce.
Swaroop Ghosh et al. (2018) have done the experimental investigation of using saw-dust as a partial replacement of sand within the properties of concrete mix. Natural sand was partially replaced with saw dust in (10%, 20%, 30% and 40%). The mixed fine aggregate was pursued through sieve size analysis together with relative density test. After this analysis of saw dust by automated spectrometer was done. This newly formed blended fineaggregate was utilized in mortar and concrete to match with natural concrete mixture. Natural fine aggregate concrete had compressive, tensile, and flexural strengths of 31.56 MPa, 3.29 MPa, and 8.56 MPa up to 28 days, respectively. These values are lower than those of concrete in which sawdust replaced sand by 10%. (35.23mpa, 3.7mpa, 8.87mpa).
Junaid et. al. (2016) made a comparison between the standard cured concrete and self-curing concrete by adding admixture polyethylene glycol (PEG-400 1%, 2% and three weight of cement) in concrete (grade ratio = 1:1.92:3.49) which helps in self-curing and inbetter hydration and hence strength. Compressive strength of concrete with 1% and a couple of PEG-400 dosage gives higher compressive strength as compared to conventionally cured concrete Thakare et.al (2016) carried experimental work to check between the Self Cured Concrete(SCC) and Conventionally Cured Concrete (CCC) for M20-M35 grade with plasticizer andwithout plasticizer (normal concrete). they concluded that the SCC gives better strength thanCCC till 14 days, at 28 days result are almost same for both concrete.

CHAPTER 3 MATERIALS FOR SAWDUST CONCRETE 3.1 General
Concrete is a hardened mass of heterogeneous materials. Its properties are influenced by a large number of variables and related to differences in types and amounts of ingredients, differences in mixing, transporting, placing and curing. The common ingredients of sawdust concrete are cement, coarse aggregates, fine aggregates, water, and saw dust. The fifth and sixth ingredient is used to modify certain specific properties of concrete mix, which is added to concrete in percentages by weight offine aggregates. Concrete mixes are created to have the appropriate properties in the fresh and hardened states, depending on the situation, by sparingly using the components available for manufacturing concrete and properly balancing their proportions. In this section the physical and chemical properties of the concrete making materials, which influence the properties of concrete mixes, are discussed.

Cement
The word cement is derived from the Latin word "cementum" which was used by the Romans to denote the rough stone or chips of marble from which a mortar was made. Thecement is a highly fine-grained substance and has cohesive and adhesive qualities that act as a binder for the separate elements. For civil engineering projects, they are limited to using calcareous cement, which primarily consists of lime compounds as one of its main elements and serves as a binder for both fine and coarse aggregate particles. Today cement finds extensive use in all types of construction works, in structure where high strength is required and also in structures exposed to the action of water. Cement mortar concrete reinforced brickwork, artificial stones, plastering, pointing and partition walls are routinely used in buildings. The raw materials required for manufacture of portable cement are calcareous materials such as limestone and chalk and argillaceous material such as shale or clay. The raw materials are ground, mixed closely in specific ratios based on their purityand composition, and then burned in a kiln at a temperature of roughly 1300 to 15000C to produce cement. At this temperature, the substance cinders, partially with the addition of 2-3 percent gypsum. By following this process, Portland cement can be produced. To function properly in structures, the cement that will be used in construction must possess a number of characteristics. The engineer is convinced that in the majority of circumstances,the cement performance will be good when these parameters fall within a specific range. The important properties are as follows.

Physical Properties of Cement • Fineness
The fineness of cement is a measurement of the size of cement particles andis stated in terms of a particular cement surface. The particle size distribution canbe used to compute it. It has a significant impact on how quickly strength increasesand how consistently quality is produced. As greater surface area is available for chemical interaction, the rate of hydration increases with cement fineness. • Colour When referring to high-quality Portland cement, the colour of the cement should be grey or greenish grey. Due to oxides of iron and manganese its colour is grey which changes with the degree of burning.

• Specific Gravity
The specific gravity of newly burned Portland cement should be at least 3 Specific gravity does not reflect the quality of the cement. The mix proportionsare calculated using it.
• Setting time The phenomena through which the plastic cement paste turns into a solid mass may be referred to as the setting time of cement. The cement setting time hasbeen arbitrarily divided into two parts: the initial setting time, which cannot be lessthan 30 minutes, and the final setting time, which cannot be more than 10 hours. The rate of setting is the maximum time allotted for mixing, transporting, putting, and compacting concrete is the rate of setting

• Soundness
It is crucial that there is no noticeable change in cement's volume after setting. When cement sets, some of its components may expand unintentionally, which makes cement unstable. Disintegration and severe cracking are caused by the significant volume shift that comes along with expansion. The cement's unsoundness is caused by the inclusion of free lime and magnesium. The Le-Chatelier and Autoclave tests are the two most important ones for soundness. It iscrucial to verify the soundness of cement to make sure it does not exhibit any discernible expansion. It is crucial to verify the soundness of cement to make sureit does not exhibit any appreciable expansion.

• Hydration
Hydration of cement refers to the chemical reaction that occurs between water and cement during the setting and hardening process. The so-called heat ofhydration is liberation as it is an exothermic reaction. The amount of heat in calories released per gram of hydration cement upon complete hydration at a specific temperature is known as the heat of hydration. The heat of hydration increases as the temperature increases where hydration takes place.

• Compressive Strength
When water is added to cement, it hydrates and exhibits cohesiveness andsolidity. Through adhesion, it holds the aggregates together. The kind and composition of cement determine the strength of mortar and concrete. The fundamental data needed for mix design is compression strength. This test allowsfor the regulation of both quantity and quality while also determining the level of adulteration.

Aggregates
Aggregates are important in concrete, basically used as filler with binding materials in the production of mortar and concrete. They are either produced from blast furnace slag or sourced from igneous, sedimentary, and metamorphic rocks. The body of the concrete is made up of aggregates, which also prevent shrinkage and improve economy. They make up between 70 and 80 percent of the concrete, thus it's important to understand more about the aggregates that constitutes more volume in concrete. The aggregate is generally utilized to give concrete bulk. The aggregate is commonly used in two or more sizes to increase the density of the resultant mix. Fine aggregate is defined as aggregate that, passes through a 4.75mm IS sieve and only contains the amount of coarser material authorized by the specifications. The fine aggregate might be natural sand, crushed stone, or crushed gravel sand. The majority of aggregate that passes through the 4.75 mm IS sieve and contains no more fine materials which are allowed by the specification is referred to as coarse aggregate.
The coarse aggregate may be uncrushed stone or gravel, partially crushed stone orgravel, or crushed stone. The fine aggregate's primary role is to aid in the production of workability and uniformity in mixtures. Additionally, the fine aggregate helps cement paste to maintain the suspension of the coarse aggregate particles. When concrete must be transported a distance from the mixing plant to the point of placement, the action encourages flexibility in the mixture and guards against potential paste and coarse aggregate segregation. To get virtually economy from paste, aggregates should be clean, hard, strong, and durable, and they should be sized according to size. Aggregates should be chemically stable, and they frequently show resistance to abrasion, freezing, and thawing.

Characteristics of Aggregates
When choosing aggregate for concrete, factors like strength, particle shape, surface roughness, specific gravity, bulk density, voids, porosity, moisture content, and bulking should be taken into account.

• Strength
Because the strength of the parent rock, from which the aggregates are created, does not perfectly correspond to the strength of the aggregate in concrete,we do not imply that strength when we talk about strength. The bond between the cement paste and the aggregates determines strength. Aggregates is very much essential in order to produce concrete that is durable. For the purpose of determining the strength of aggregate, three tests are often required: the crushing value, the impact value, and the 10% fines value. The standards limit the crushingvalue at 45 percent. For the wearing surface and the remaining concrete, the impactvalue should not be more than 30 and 45 percent, respectively. Toughness and hardness are two additional mechanical characteristics of aggregates that are connected. According to the aggregate abrasion value, thehardness of the aggregate is determined by its resistance to wear.

• Aggregate Size
The highest maximum size of aggregate that can reasonably be handled under a specific set of circumstances should be used. The cement content and drying shrinkage will both be reduced by using the largest maximum size. The largest size of aggregate that can be utilized in a given situation may be restrictedby the section thickness, the distance between the reinforcement, the clear cover, the mixing, handling, and placement methods. The aggregate's maximum size should be as large as possible within the prescribed range, but in no circumstanceshould it be greater than 1/4 of the member's maximum thickness.
• Shape of aggregates Shape is one of the physical characteristics, which influences the workabilityof fresh concrete and the bond between the aggregate and the mortar face. In general, there are four types of aggregates: spherical, irregular, angular, and flaky. Round aggregates are preferred over angular aggregates from the conventional point of economy in cement required for a given water-cement ratio. Excessivelyflaky aggregate make concrete poor • Texture of aggregate The proportional degree to which particle surfaces are polished or dull, smooth or rough, determines the surface texture's measurement. The surface texture affects how well aggregate and cement paste adhere to one another. The bond, which depends on the aggregate's surface porosity and roughness, develops mechanical anchoring. The compressive and flexural strength of concrete can be increased by up to 20 percent by using aggregate with a rough, porous texture as opposed to one with a smooth surface, which can enhance the aggregate cement bond by 75 percent.

• Specific Gravity
The specific gravity of an aggregate is defined as the ratio of the mass of solid in a given volume of sample to the mass of an equal amount of water at the same temperature is known as the specific gravity of an aggregate. Most naturallyoccurring aggregates have a specific gravity between 2.6 and 2.7.

Water
Water is the inexpensive component of concrete. Aside from the water used for mixing cement, which is used to hydrate it, water is also used to create the binding matrix, which holds the inert aggregate in suspension until the matrix has set. The residual water makes concrete workable by acting as a lubricant between the fine and coarse particles. For hydration, cement needs around 3/10th of its weight in water. The needed water cement ratio must be at least 0.35. But concrete that contains this amount of water will be incredibly harsh and challenging to place. Additional water is needed to lubricate the mixture, which makes concrete workable. Concrete should only require the bare minimum additional reinforcement in order to limit further strength loss. Water is essential for the formation of the cement gel that gives concrete its strength, so the quantity and quality of water must be carefully considered. Concrete mixing and curing require the use of water that is free of harmful levels of harmful substances. For mixing concrete, portable water is often regarded as satisfactory.

Sawdust
Government officials and corporate developers are worried about the rising expenses of building projects in developing nations. The use of sawdust as a partial replacement for fine particles in the making of concrete was the subject of this investigation. Sawdust is not a widely used substance in the building industry. This is either because to the fact that it is not readily available as sand or gravel, or it is because their use for such purposes has not been promoted. Recently index, and other qualities alter as a result.

Fig I: Sawdust used for experiment 3.6 Self-curing compound
Concure WB is a low viscosity emulsion-based water-based concrete curing product. It comes in the form of a white emulsion that dries to form a clear film. The emulsion splits when first applied to a brandnew cementitious surface, forming a continuous, non-penetrating white coating.

Tests on manufactured sand 4.2.1 Sieve analysis of fine aggregates:
Objective: To determine the particle size distribution of fine aggregates by sieving Standard: IS 2386 (part 1) -1963 Procedure: The test was conducted as per IS 2386 (part 1)-1963 and results obtained areas follows Observation: Weight of fine aggregates taken: 1Kg

Chapter 6 EXPERIMENTAL INVESTIGATIO 6.1 General
Concrete's most significant and practical property is its compressive strength. Concrete is generally used in structural applications to resist compressive stresses. The main aim of this investigation is to monitor the above said parameters of concrete in which certain percentage of saw dust and deformed steel fibers are added by weight of fine aggregates and cement respectively.

Experimental Procedure
The main aim of the present experimental investigation is to study the behavior of concrete containing saw dust in compression. The study is made considering 0% (reference mix), 10%, 20% of saw dust.
• 150mmX150mmX150mm concrete cubes are cast and tested for compressive test.
• M30 concrete mix design as per IS: 10262 is used in the present work. The details of mix design are presented in the earlier chapter.

Batching
Concrete is batch-mixed, which means that the cement, sand, coarse aggregate, and water are all measured separately before being combined. There are two distinct batching methods. ➢ Volume batching ➢ Weight batching The correct way to measure the ingredients is technically through weigh batching. 36 cubes measuring 150mmx150mmx150mm were casted for the current experimental study. As a result, the batching of the materials needed for casting was decided according to the mix proportion, taking a 10% wastage into account. When weigh batching is used, accurate water measurement is required.

Mixing
The process of completely blending the components needed to create homogenous concrete is known as mixing concrete. The primary goal of mixing is to produce homogenous, workable concrete. There are two methods used for mixing concrete.
• Hand mixing • Machine maxing For small-scale, minor concrete jobs, hand mixing is used. In order to compensate for the subpar concrete generated by this approach, it is desirable to add 10% additional cement as the mixing cannot be thorough and efficient. For reinforced concrete work and medium-to large-scale mass concrete projects, concrete mixing is nearly always done by machine. When there is a lot of concrete to manufacture, machine mixing is not only effective but also cost-effective. During the current experiment, batch mixers were employed. The typical speed range for concrete mixers is 15 to 29 revolutions per minute. In a well-designed mixer, it is observed that between 25 and 30 revolutions are necessary for proper mixing. Using a batch mixer equipment and the components needed to make nine cubes of size 150mm , concrete was mixed in a laboratory setting. The concrete is then placed into a dry, thoroughly cleaned tray for casting. Later, mixing took place.

Measurement of workability
The ease with which concrete may be mixed, poured, compacted, and finished is what is meant by the term "workability" of the material. The presence of a particular amount of water is crucial for providing the lubrication needed to handle concrete without segregation, to place without losing homogeneity, to compact with the amount of work required, and to complete it easily enough. Water content, aggregate size and shape, aggregate surface roughness, mix proportion, usage of admixtures, aggregate grading, and other variables all affect how workable a material is. The workability of concrete can be determined using a variety of techniques. The most widely used workability measurement tests based on concrete stiffness are the slump test, compaction factor test, and Vee-Bee consistency test. The current experimental study uses the concrete slump test to measure the concrete's workability.

Slump Test
The apparatus is made up of a base plate and a metallic cone-shaped mould with the following interior dimensions. Bottom diameter:20cm Top diameter:10cm Height: 30cm The slump test apparatus was oiled before four layers of concrete were added, each of whichwas tamped 25 times before the surface was smoothed up. The fresh concrete is then left to settle as the slump cone is lifted up. The slump value determines workability of concrete. After the mould has been removed, the vertical distance from the top of the cone to the falling concrete is known as the slump value. When slump value increases, workability of concrete also increases

Casting
It is time to cast the concrete cubes once the freshly mixed concrete has been poured into the tray and its workability has been measured. The empty moulds are prepared, cleaned and oiled. The cubes are filled with three layers of concrete, each of which is tamped 25 times.

Compaction of concrete
The method used to release the trapped air from the concrete is called compaction. Air is likely to become trapped in the concrete during the mixing and placement processes. The amount of air trapped increases as workability decreases. In other words, stiff concrete mix would require more compacting effort than high workable mixtures since it has a high percentage of trapped air. Concrete in the current work is compacted using a table vibrator.

Curing
Concrete cures as a result of a chemical reaction between the type of cement in the concrete and the water. Hydration describes the reaction between water and cement. Curing is the process by which concrete hardens and gains strength. Six of the cubes were preserved after demoulding for water curing in the curing tank, and the other six were kept for self-curing, where we coated them with a chemical compound and continually cured them for seven and a twenty eight days before testing. This offers adequate curing.

Compressive strength
On hardened concrete, the compressive strength test is the most frequently used. One of the key requirements for structural design is compression strength, which makes sure the structure can support the intended load. As the water cement ratio decreases, compressive strength increases. The cube compression test is used to test the strength of crushed concrete cubes in a destructive manner. This test will provide the cube's breaking strength, which is made specifically to measure the compression strength of compacted concrete.   Table V gives the slump values of fresh concrete with sawdust. The slump gradually decreases from 10% to 20% use of sawdust. The decrease in the slump is shown in the figure X.

CHAPTER 8 CONCLUSIONS
The following are the conclusions that are drawn from the experimental investigations conducted on Sawdust concrete. • The utilization of Saw dust in concrete provides additional environmental as well as technical benefits for all related industries. Partial replacement of sand with Sawdust reduces the cost of making concrete. • Saw dust concrete is light weight in nature and it proves to be environment friendly, thus paving way for green concrete. • The result of compressive test indicated that the strength of concrete decreases with respect to the percentage of Saw dust added (10% and 20%). As the percentage sawdust content increased in the mix the compressive strength decreased. • By comparison between conventionally cured concrete and self-cured concrete with respect to its compressive strength and density, we can conclude that compressive strength of conventionally cured concrete gives better result than self-cured concrete. • There is reduction in density of sawdust concrete with increase in percentage of sawdust in concrete and also there is decrease in density of self-cured concrete as compared with conventionally cured concrete. • Optimum replacement of sand with sawdust has been found to be 10% Beyond this limit, the concrete produced did not meet code requirements for strength as per BS 8110 (1997). Therefore, the strength was achieved when the replacement was donefor 10% whereas the strength was not achieved when the replacement was done for20%. • Use of sawdust as a waste in concrete decrease the pollution which is caused after burning of sawdust.