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CHAPTER 1 INTRODUCTION
Water hyacinth is a free-floating perennial aquatic plant that mostly occurs in tropical countries. They may rise above the water surface by as much as one meter in height. If not controlled, this plant will cover the rivers, lakes, and ponds. This will then lead to blocking of sunlight from reaching the other aquatic plants and dramatically affects the flow of water that may further lead to flooding. 1.1 Background of the Study
In Cotabato City, water hyacinth is a major problem as it is one of the major causes of flooding. It occupies the rivers and the seas and blocks the flow of water. People are collecting them and turning them into recycled bags, wallets, and other stuff. However, these processes still do not solve the problems on water hyacinth. The researchers thought of ways on how to convert them into additives on mortars and help eliminate the problems on water hyacinth. Retarders are additives designed for areas where early setting of concrete is not preferable. Examples of this are high ambient temperatures, long travel times between concrete plants and job site, large slow pours – pours – to to prevent formation of cold joints and others. The chemical composition of retarders is formulated to temporarily stop the action of hydration, delaying the setting time for concrete. Setting time of concrete is the time at which cement paste loses its plasticity. On the other hand, an accelerator accele rator is an admixture for the use in concrete, in concrete, mortar, mortar, rendering or screeds. The addition of an accelerator speeds the setting time and thus cure time starts earlier. This allows concrete to be placed in winter with reduced risk of frost damage. That’s how the researchers came up with the idea of using water hyacinth as additives, specifically as an accelerator or a retarder. This is to help people in need
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of extending or speeding up the setting time of concrete and at the same time, help solve problems on water hyacinth in the community. This is done by converting water hyacinth into ashes and apply it as additives on concrete. 1.2 Statement of the Problem
To determine the relationship between water hyacinth ash as additives in cement and the setting time of the mortar. 1.3. Objectives of the study
This study sought to determine how water hyacinth ash as additives on cement in mortar affects the setting time. Specifically, this study aimed to determine the following: 1. To determine whether the water hyacinth ash as additives for cement mortar can be an accelerator or retarder; 2. To determine the effect of adding different weight percentage of water hyacinth ash to the setting time of mortar; 3. To determine the difference in compressive strength of the cement mortar at the maximum setting time to that of a normal mix; 4. To determine the relationship of the percent cement replacement and the compressive strength of the concrete; 1.4 Significance of the Study
This study could help reduce or eliminate the quantity of water hyacinth in the Cotabato City specifically in the Rio Grande de Mindanao River. This study also aims to help extend the time ti me needed by truck mixers to deliver the t he concrete mix to the site before the mix sets.
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of extending or speeding up the setting time of concrete and at the same time, help solve problems on water hyacinth in the community. This is done by converting water hyacinth into ashes and apply it as additives on concrete. 1.2 Statement of the Problem
To determine the relationship between water hyacinth ash as additives in cement and the setting time of the mortar. 1.3. Objectives of the study
This study sought to determine how water hyacinth ash as additives on cement in mortar affects the setting time. Specifically, this study aimed to determine the following: 1. To determine whether the water hyacinth ash as additives for cement mortar can be an accelerator or retarder; 2. To determine the effect of adding different weight percentage of water hyacinth ash to the setting time of mortar; 3. To determine the difference in compressive strength of the cement mortar at the maximum setting time to that of a normal mix; 4. To determine the relationship of the percent cement replacement and the compressive strength of the concrete; 1.4 Significance of the Study
This study could help reduce or eliminate the quantity of water hyacinth in the Cotabato City specifically in the Rio Grande de Mindanao River. This study also aims to help extend the time ti me needed by truck mixers to deliver the t he concrete mix to the site before the mix sets.
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1.5 Scope and Limitations
The study focused on determining the effect of water hyacinth ash as additives to the setting time of concrete mix. In this study, the water hyacinth will only be coming from Rio Grande de Mindanao River. The study will also be conducted within Cotabato City. The percentage of additives to be used are 0%, 5%, 10% and 15% with curing time of 7, 14, and 28 days. 1.6. Conceptual Framework
To properly understand the concept behind determining the relationship of percentage of WHA added and the setting time of cement mortar, Figure Figure 1.1 shows the conceptual framework of this research. Figure 1.2 shows the concept on determining the compressive strength of cement mortar with 15% WHA additive at maximum curing period.
Figure. 1.1
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Figure. 1.2
1.7. Definition of Terms Water hyacinth – is an aquatic plant native to the Amazon basin, and is often
highly problematic invasive species outside its native range Water hyacinth ash (WHA) – is a non-aqueous, non-gaseous residue remained
after burning water hyacinth Setting time of concrete – is defined as the specific time required for concrete or
mortar to change from liquid state to plastic state, and plastic state to solid state Additives – a substance added to something in small quantities, typically to
improve or preserve it Retarders – are additives used to decrease the rate of cement hydration Penetration resistance method – is a method that covers the determination of the
time of setting of concrete, with slump greater than zero, by means of penetration resistance measurements on mortar Mortars – is a workable paste used to bind building blocks such as stones, bricks
and concrete masonry units together and fill and seal the irregular gaps between them
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Cement – is a substance used for construction that sets, hardens and adheres to
other materials, binding them together.
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CHAPTER II
REVIEW OF RELATED LITERATURE
2.1 Water Hyacinth ( E ichhornia Crassipes)
2.1.1 Definiton
Originally
from
South
America,
water
hyacinth, Eichhornia
crassipes (Mart.) Solms, is one of the world’s most prevalent invasive aquatic plants. Water hyacinth, a free-floating vascular plant, is known to cause major ecological and socio-economic changes (Center, 1994). It commonly forms dense, interlocking mats due to its rapid reproductive rate and complex root structure (Mitchell, 1985). Water hyacinth reproduces both sexually and asexually. Seeds generally germinate within six months, with dry conditions promoting germination (Ueki & Oki, 1979). Low nutrient concentrations and temperature (air and water) are considered the strongest determinants for water hyacinth growth and reproduction (Wilson et al., 2005). Salinity generally limits water hyacinth establishment in coastal areas and within estuaries, although at least one case of such is documented (Mangas-Ramirez & Elias-Gutierrez, 2004). Water hyacinth is not restricted to shallow water like many submersed and emergent macrophytes because its roots are free-floating near the surface of the water.
Water hyacinth has invaded freshwater systems in over 50 countries on five continents and, according to recent climate change models, its distribution may expand into higher latitudes as temperatures rise (Rodríguez-Gallego et al., 2004; Hellmann et al., 2008; Rahel & Olden, 2008). Water hyacinth is especially pervasive throughout Southeast Asia, the southeastern United States, central and western
Africa
and
Central
America
(Bartodziej
&
Weymouth,
1995; Brendonck et al., 2003; Lu et al., 2007; Martinez- Jimenez & Gomez-
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Balandra, 2007). It is prevalent in tropical and sub-tropical wat erbodies where water nutrient concentrations are often high due to agricultural runoff, deforestation and insufficient wastewater treatment. There is not a clear record of how, why and when water hyacinth was introduced to waterbodies outside of its native range, but many populations are well established and persistent despite control efforts. Introductions to non-native waterbodies have been accidental and intentional; intentional introductions to ponds are common as water hyacinth is an ornamental plant that reduces nutrient concentrations and algae blooms. Its success as an invader is attributed to its ability to outcompete native vegetation and phytoplankton and the absence of consumers found within its native range such as Neochetina eichhorniae Warner
and Neochetina
bruchi Hustache
(Wilson et al., 2005).
Invasions vary in extent and duration, but generally cause similar problems. Changes to water hyacinth density have the potential to affect other ecological and human communities in areas where it is established; these changes may be perceived as positive or negative depending on the designated or beneficial uses of the waterbody (Gibbons, Gibbons & Sytsma, 1994).
Water hyacinth is extremely difficult to eradicate once established. Therefore, the goal of most management efforts is to minimise economic costs and ecological damage. Recent literature on the management of water hyacinth focuses on techniques to remove the weed; however, little has been done to assess the full extent of ecological changes (i.e. abiotic and biotic) that may occur in response to the establishment and management of this non-native species. Determining the consequences of controlling an established water hyacinth population is conti ngent on our ability to understand how water hyacinth affects the s ystems that it inhabits. There are very few studies that report the ecological conditions prior to invasion (Abu-Gideiri & Yousif, 1974). This makes it difficult to understand fully how water hyacinth alters an ecosystem. We rely on scientific accounts that either compare water quality and ecological condition between sites with and without water hyacinth, or examine the changes that occur after a control programme is
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implemented. Many investigations focus on one element of an ecosystem at a time (e.g. nutrient concentration, dissolved oxygen, plant or animal community composition); however, it is necessary to look at effects on the system as a whole to comprehend the direct and indirect impacts of this aquatic plant. (A. M. VILLAMAGNA, B. R. MURPHY, 2009)
2.1.2 Properties
About 21 components were identified in this analysis. Compounds belonging to ketones, aldehydes, alcohols and fatty acids were recorded. Out of these, the components highlighted in S. No. 14, 15 and 16 namely: Hexadecanoic acid, methyl ester, 9-Hexadecenoic acid and n-Hexadecanoic acid are Palmitic acid groups. Moreover, the fatty acid components-Octadecadienoic acid (common name linoleic acid) is also identified. The possible components identified are presented in Table 1. Chromatogram of GCMS analysis of Water Hyacinth is presented in Fig. 9.
In general, lignin, cellulose and hemi cellulose improves the binding and cementing of the grains of cement compounds as observed in the scanning electron micrograph of cement mortar cubes replaced with bio extract as shown in Fig. 10. The filtrate of water extract of Water Hyacinth could contain dissolved small fragments of lignocelluloses which could have partially dissolved in water could multiply the binding effect of these compounds on cement.
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Figure 9 Chromatogram of GCMS analysis of water hyacinth
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Figure 10(a-b): Scanning electron micrograph crystallisation pattern
of bio extract and cement mortar (a) Control 0% replacement
and
(b)
20%
replacement
with
bioentract According to Hewlett (1988), lignin is a water-reducing agent but accelerator of setting of cement due to increased binding.
The second main component is the fatty acid groups. Presence of fatty acids such as palmitic acid and linoleic acid could very well answer the reason for delayed
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setting time and increased compressive strength. The squeezed out extract from Water Hyacinth which contains suspended insoluble molecules of fatty acids hampers the rate of setting time by hampering the evaporation of water molecules from the mixed paste. As the amount of percentage of bio admixture increased, the setting time also increased as fatty acid content increases with increase in extract volume.
Moreover, the fatty acid components improve the binding capacity among the grains of cement owing to their complex fatty acid chain structure. It has been reported by CCAA (2009) that admixtures consisting fatty acids, such as oleic acid; stearic acid; salts of calcium oleate and esters, such as butyloleate, are typically used to reduce the penetration of corrosive agents into concrete clinker and moreover, as the palmitic acid and linoleic acid are insoluble in water, they could not possibly penetrate into cubes thereby delaying the setting time and prevents the penetration of other corrosive agents and hence the reduction in sorptivity has been observed with increase in time.
The composition clearly highlights about the presence of saturated fatty acid- palmitic acid which poses threat to the stability of cement cubes as it could remain ‘non-drying’ so, there is chance for development of rancidity which attacks the concrete. But the action of palmitic acid could have been well balanced by the presence of another component-‘linoleic acid’ which is an unsaturated fatty acid which reacts with exposed air and moisture and takes up the oxygen to form fully saturated hydroxy acids which could provide an impervious skin to t he surface of cement cubes thereby preventing any instability in st ructure. Moreover, presence of appreciable content of di-unsaturated esters of linoleic acid is prone to polymerization reactions when exposed to oxygen in air (Hewlett, 1988). Thus, polymerization which is called "drying," could result in the rigidification of the cement cubes displaying increase in compressive strength with the increase in
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percentage of bioadmixture-the hydro-extract of Water Hyacinth. (A. Sathya, P. Bhuvaneshwari, G. Niranjan and M. Vishveswaran, 2014)
2.2 Setting Time
Setting properties of concrete is the most important part in the field of concrete construction (Brooks et al., 2000). It helps in the development of different kinds of concreting operations such as transporting, placing, compacting and finishing of concrete. Placement of concrete in formwork depends on the setting time of concrete, which makes the concrete rigid (Clear and Harrison, 1985). Nowadays production of new generation concrete like geopolymer concrete, selfcompacting concrete, high strength concrete, and high performance concrete has been increasing throughout the world. For their better performance and to achieve better engineering properties, mineral admixtures such as fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK) and rice husk ash (RHA) are normally added as partial replacement of cement for the better performance of advanced concrete. Since the different mineral admixtures possess different chemical and mineralogical compositions as well as different particle characteristics, they could have different effects on the properties of concrete inclusive of the setting characteristics. Knowledge of the setting characteristics is important in the field of concrete construction. This will help in scheduling the various stages involved in concrete construction operation such as transporting, placing, compacting and finishing of concrete. Such information is necessary when deciding whether or not to use a retarding admixture or accelerator. (International Journal of Sustainable Built Environment, June 2017)
Initial setting time of concrete is measured based on penetration resistance of mortar sieved from concrete and it is considered as the time taken to achieve a penetration resistance of 3.5MPa which is an arbitrary value. The main objective of this research is to find a test method to obtain a realistic initial setting time value in
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order to plan the placing of concrete to prevent formation of cold joints which can affect the performance of the structure. Mechanical properties (tensile strength and shear strength) at a purposely made cold joint was evaluated by testing concrete cubes cast in two layers with different time lags between placing of concrete in the two layers. Point of change of each strength parameter with respect to time lag was identified and corresponding time range was identified as the initial setting time range. Standard penetration resistance test was also carried out and with the use of penetration resistance vs. elapsed time graph, corresponding penetration resistance value was also identified. Although this new method is effective to identify the initial setting time of concrete, it is not possible to use as a field test since it a time consuming and complicated test. Therefore, an attempt was made to introduce a simple field test method. Ultrasonic pulse velocity is used to measure properties of hardened concrete, because pulse velocity of a concrete sample depends on its elastic modulus and density. Since properties of fresh concrete such as elastic modulus changes with time, the ultrasound pulse velocity was used to monitor the change of stiffness of fresh concrete with time. Based on the test results of the experimental investigations, it was found that the more realistic initial setting time of concrete is the onset time of the penetration resi stance of mortar measured in the standard penetration test. This was further verified by a simple qualitative field test where the initial setting time is considered as the latest time that a vibrating poker can be inserted into the concrete and removed without leaving a significant trace. (American Society for Testing and Materials, Pennsylvania,1999)
2.2.1 Additives
Cement additive, which is evolved from grinding aids, is a special chemical agent that is used to intergrind with clinker to increase the grinding efficiency of ball mill and to improve the performance of finished cement. Among the requirements on the modification of cement performance, strength improvement is one of the primary targets. Only in this way can the clinker be replaced by some
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industrial by-products so that the cost of finished cement can be reduced. Traditional strength activator for cementitious materials is chloride which i s widely used as the setting and hardening accelerator. For concrete curing at 20 °C, an addition of 2% CaCl2H2O in mass fraction of cement can double the one-day compressive strength. However, the problem is that chloride brings corrosion to steel fiber in reinforced concrete. Thus, some other non-corrosive accelerators were studied. They were calcium formate, Ca(CHO2)2 and calcium nitrate, Ca(NO3)2. In industry, when liquid cement additive is formulated, Ca(NO3)2 is frequently used due to its cost efficiency and high solubility. Some studies show that the eff ect of Ca(NO3)2 is tended to be dependent on the contents of aluminate and belite in cement. In recent years, organic accelerators become widely accepted because of their low effective addition in cement. Alkanolamines such as triethanolamine (TEA) and triisopropanolamine (TIPA) are the general grinding chemicals which are added in the comminution process of cement manufacture. They are also formulated and used in some of the chemical admixtures, with which the mechanical performance of concrete can be improved by accelerating the hydration of specific mineral compounds of cement. On the other hand, workability is also one of the key criteria to evaluate the rheological performance of cementitious materials. In order to enhance the workability of concrete, sa ccharides, which could be adsorbed on the surface of cement gains and hydrates, are often used as retarders to prolong the setting of fresh mix, and then additionally prohibit the further agglomeration among particles. As a result, the viscosity of fresh mix decreases, and the workability can also be improved in a certain degree. (Progress in Natural Science: Materials International Volume 21, Issue 3, June 2011)
2.2.1.1 Accelerators
Accelerators are one of the most popular kinds of chemical admixtures. Like water reducers, retarders and plasticizers, when added to a concrete batch either
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immediately before or during mixing. To kick the set time of a batch of concrete into high gear, hit the accelerator. Like water reducers, retarders and plasticizers, accelerators are one of the most popular kinds of chemical admixtures, added to a concrete batch either immediately before or during mixing. Accelerators make concrete set faster, also known as increasing the rate of hydration. At the same time, they promote strength development so it happens earlier in the set time of a s lab. If a contractor is using an accelerator, the odds are good that the weather is wintry. Accelerators counteract the influence of cold weather, which slows down the curing and setting process. But accelerators aren't just for cold weather. A contractor can use one anytime a curing process needs a kick. The admixture may allow a concrete worker to remove forms earlier, get onto a concrete surface earlier for finishing, and sometimes even put loads on it earlier, such as when diverting foot traffic to do patching. “Decorative guys will use accelerators in summer. It helps control the process when stamping,” says Terry Collins, concrete construction engineer with the Portland Cement Association. If an accelerator is added to concrete on one half of a pour, a contractor can start stamping on that side, work his way to the other side, and enjoy a relatively consistent level of workability throughout. Decorative contractors have been using retarding admixtures for several years to achieve this effect, says Gabriel Ojeda, president of concrete admixture manufacturer Fritz-Pak Corp., and accelerators can pull off more or less the same trick. Because accelerators cut set time, they can reduce labor costs, Ojeda says. They can also hasten the time an indoor remodel job, such as a cast-in-place countertop, takes to set, Ojeda says. “You don't want people to have to wait seven, 10, 15 days without being able to use their kitchen,” he says. (John Strieder, Nov 9, 2005)
2.2.1.2 Retarders
Retarding admixtures have little or no effect other than to delay the setting of the cement. They do not plasticise significantly and have no effect on the water
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demand or other properties of the concrete. Retarding plasticising admixtures not only delay the setting of the cement but are also efficient plasticising waterreducers. Most commercially available retarders are of this type. Retarding plasticisers are used to give workability retention to the concrete, dela y the setting time and increase initial workability.
As with plasticisers, ultimate strength gain increases as water is reduced. Set retardation allows the slower formation of a more ordered, smaller, denser cementitious matrix. This increases ultimate strength relative to an unretarded mix with the same w/c ratio.
Provided that the concrete is correctly cured, retarded concrete should be stronger and just as durable as equivalent plain concrete. However, because of the extended plastic stage, more attention needs to be paid to protecting it before it sets. Retarded plasticised concrete will also contain less water than the equivalent plain concrete and will be correspondingly more durable. (The Concrete Society)
2.3 Mortar
Mortar, in building, mixture of lime or cement with sand and water, used as a bedding and adhesive between adjacent pieces of stone, brick, or other material in masonry construction. Lime mortar, a common variety, consists usually of one volume of well-slaked lime to three or four volumes of sand, thoroughly mixed with sufficient water to make a uniform paste easily handled on a trowel. Lime mortar hardens by absorption of carbon dioxide from the air. Once universally used, lime mortar is now less important because it does not have the property of setting underwater and because of its comparatively low strength. It has largely been supplanted by cement mortar, commonly made of one volume of Portland cement to two or three volumes of sand, usually with a quantity of lime paste added to give a more workable mix. Cement mortar, besides having a high strength, generally
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equal to that of brick itself, has the very great advantage of setting or hardening underwater. Other varieties include gauge mortar, for rapid setting, composed of plaster of Paris used either pure or combined with lime or with lime and sand, and grout, a thin liquid mixture of lime or cement, poured into masonry to fill up small interstices. Primitive mortars took various forms: in early Egypt, Nile mud was used as an adhesive; the Mesopotamians used bitumen (the slime mentioned in Genesis) or sometimes a mixture of clay, water, and chopped straw, to cement together their unbaked bricks; Greeks of the Mycenaean era probably employed a soft bituminous clay. The advanced Greek buildings are notable for their construction without mortar, the huge blocks of stone being consummately fitted with dry beds. The Romans likewise used little mortar in cut stonework or vaulting but in later periods bedded the rough stone of their mass masonry in strong cement mortar. In medieval times and in all periods since, mortar of some sort has been almost universally used in masonry construction. (The Columbia Encyclopedia, 6th ed.)
2.3.1 Aggregates
Aggregates are inert granular materials such as sand, gravel, or crushed stone that, along with water and portland cement, are an essential ingredient in concrete. For a good concrete mix, aggregates need to be clean, hard, strong particles free of absorbed chemicals or coatings of clay and other fine materials that could cause the deterioration of concrete. Aggregates, which account for 60 to 75 percent of the total volume of concrete, are divided into two distinct categories-fine and coarse. Fine aggregates generally consist of natural sand or crushed stone with most particles passing through a 3/8-inch sieve. Coarse aggregates are any particles greater than 0.19 inch, but generally range between 3/8 and 1.5 inches in diameter. Gravels constitute the majority of coarse aggregate used in concrete with crushed stone making up most of the remainder.
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Natural gravel and sand are usually dug or dredged from a pit, river, lake, or seabed. Crushed aggregate is produced by crushing quarry rock, boulders, cobbles, or large-size gravel. Recycled concrete is a viable source of aggregate and has been satisfactorily used in granular subbases, soil-cement, and in new concrete. After harvesting, aggregate is processed: crushed, screened, and washed to obtain proper cleanliness and gradation. If necessary, a benefaction process such as jigging or heavy media separation can be used to upgrade the quality. Once processed, the aggregates are handled and stored to minimize segregation and degradation and prevent contamination. Aggregates strongly influence concrete's freshly mixed and hardened properties, mixture proportions, and economy. Consequently, selection of aggregates is an important process. Although some variati on in aggregate properties is expected, characteristics that are considered include:
grading
durability
particle shape and surface texture
abrasion and skid resistance
unit weights and voids
absorption and surface moisture
Grading refers to the determination of the particle-size distribution for aggregate. Grading limits and maximum aggregate size are specified because these properties affect the amount of aggregate used as well as cement and water requirements, workability, pumpability, and durability of concrete. In general, if the water -cement ratio is chosen correctly, a wide range in grading can be used without a major effect on strength. When gap-graded aggregate are specified, certain particle sizes of aggregate are omitted from the size continuum. Gap-graded aggregate are used to obtain uniform textures in exposed aggregate concrete. Close control of mix
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proportions is necessary to avoid segregation. (PCA, America’s Cement Manufacturers)
2.3.2 Cement
Cement is a finely milled mineral powder, usually grey in colour. The most important raw materials for the production of cement are limestone, cla y, and marl. Mixed with water, cement serves as an adhesive to bind sand, gravel, and hard rock in concrete. Cement hardens both in the air and under water, and remains in its hardened state once reached. Cement is usually available in the form of a homogeneous bulk dry good. It’s characteristics are standardised in order to ensure the required stability, reliability, and processability in the application. Cements are classified according to their early and final strength as well as their composition. In addition to cements that consis t of 100% clinker, there are socalled composite cements, in which a portion of the clinker is replaced by alternative raw materials, such as fly ash, ground slag, or limestone. As the production of clinker is energy-intensive and releases large amounts of CO2, the use of alternative raw materials can conserve natural resources and reduce CO2 emissions. Depending on the desired application, different types of cement – each with a specific composition – are necessary. Cement characteristics can also be modified through the use of additives. We offer our customers a broad range of cement products, including quality cements, special cements with targeted characteristics, special geotechnical building materials and an expanded range of binders. Our product portfolio varies from country to country. (Heidelbergcement Group)
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2.3.3 Fine Sand
The aggregate or main part of mortar is sand. The sand is dredged from pits or river beds and a good sand should consist of particles ranging up to 5 mm in size. In the ground, sand is usually found mixed with some clay earth which coats the particles of sand. If sand mixed with clay is used for mortar, the clay tends to prevent the cement or lime binding the sand particles together and in time the mortar crumbles. It is therefore important that the sand be thoroughly washed so that there is no more than 5% of clay in the sand delivered to the site. Sand which is not washed and which contains a deal of clay in it feels soft and smooth when held in the hand, hence the term soft sand. Sand which is clean feels coarse in the hand, hence the term sharp. These are terms used by craftsmen. When soft sand is used, the mortar is very smooth and plastic and it is much easier to spread and to bed the bricks in than a mortar made of sharp or clean sand. Naturally the bricklayer prefers to use a mortar made with soft or unwashed sand, often called ‘builders’ sand’. A good washed sand for mortar should, if cl enched in the hand, leave no trace of yellow clay stains on the palm. (Civil Construction Tips, January 10, 2011)
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CHAPTER III METHODOLOGY AND PROCEDURE
This chapter presents the Research Design, Research Procedures, Research instrument, Gantt chart, Budgetary Requirements and Tasking. 3.1 Research Design
This study used experimental research design specifically the single-group design. In this study, the setting time of mortar cement is subjected to WHA additive in different percentage added namely 0%, 5%, 10%, and 15%. F-test or analysis of variance (ANOVA) is used to determine the relationship between the percentage added and the setting time of the cement mortar. 3.2 Research Procedures
To achieve this study, the following research procedures must be followed: 3.2.1. Identification of the sources of materials and instruments to be used for the experimentation The water hyacinth will be gathered from the Rio Grande de Mindanao River, Cotabato City (see Fig 3.1). The research instruments to be used as well as the Testing Machine for the compressive strength of the cement mortar will be coming from the Soil Laboratory of Notre Dame University.
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Figure 3.1 Vicinity Map of Rio Grande de Mindanao
3.2.2. Gathering and drying of water hyacinth 1. Collect an enough amount of water hyacinth 2. Wash the collected water hyacinth to remove impurities 3. Leave it in a secured room and air dry 4. Place it inside the oven and oven dry 3.2.3. Burning of water hyacinth into ashes 3.2.4. Making of mortar cement specimens with WHA additive of 0%, 5%, 10%, and 15% of the total weight of mortar 1. ASTM Sieve Analysis a. Oven dry finer aggregates b. Select set of sieves with suitable openings as required by the material’s specifications
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c. Pile the set of sieves in decreasing order and place aggregates on top d. Use mechanical vibrator or manually agitate the set of sieves e. Collect the fine aggregates that passed no. 40 sieve 2. Mixing for mortar a. Spread out the measured quantity of sand uniforml y on the mixing platform. Dump the cement on the sand and distribute it uniformly. Mix the sand and cement with the shovels, turning the mixture over and over again until it is uniform in colour. b. Make a depression in the middle of the mixed pile and pour slowly into half to three-quarters of the total quantity of water required. c. While the material is turned in towards the centre with shovels, add the remainder of the water slowl y, turning the mixture over and again until the colour and consistency are uniform throughout the pile. This will indicate that all ingredients are thoroughly combined. The water should be poured slowly into the mix. Throwing water from a bucket all at a time will result in its running away and taking cement with it 3. Making of mortar cement specimens with WHA additive of 0%, 5%, 10% and 15% of the total weight of the mortar a. Place the mold on a smooth horizontal non-porous base plate b. Fill the mold with the prepared mix in 3 approximately equal layer
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c. Tamp each layer with 25 strokes of the rounded end of the tamping rod in a uniform manner over the cross section of the mold. d. Remove the excess concrete and level the surface with a trowel e. Raise the mold from the mix immediately and slowly in a vertical direction f. Measure the slump as the difference between height of the mold and that of height point of specimen being tested. g. Fill the mold again with the prepared mix in 3 approximately equal layer each tamped with 25 strokes. Remove excess mix on the mold g. Place specimen in a secured room and leave it for 24 hours. 5. Determining the amount of setting time for specimens
by Penetration
Resistance Method a. Just prior to making a penetration test, remove bleed water from the surface of the mortar specimens by means of a pipet or suitable instrument. To facilitate collection of bleed water, tilt the specimen carefully to an angle of about 10° from the horizontal by placing a block under one side 2 min prior to removal of the water. b. Insert a needle of appropriate size, depending upon the degree of setting of the mortar, in the penetration resistance apparatus and bring the bearing surface of the needle into contact with the mortar surface. Gradually and uniformly apply a vertical force downward on the apparatus until the needle penetrates the mortar to a depth of 1 6 1⁄16 in. [25 ± 2 mm]. The time required to penetrate to the 1 -in. [25-mm] depth shall be 10 ± 2 s. Record the force required to
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produce the 1-in. [25-mm] penetration and the time of application, measured as elapsed time after initial contact of cement and water. Calculate the penetration resistance by dividing the recorded force by the bearing area of the needle, and record the penetration resistance. In subsequent penetration tests take care to avoid areas where the mortar has been disturbed by previous tests. The clear distance between needle impressions shall be at least two diameters of the needle being used, but not less than 1⁄2 in. [15 mm]. The clear distance between any needle impression and the side of the container shall be at least 1 in. [25 mm]. c. For conventional concrete mixtures at laboratory temperatures of 68 to 77°F [20 to 25°C], make the initial test after an elapsed time of 3 to 4 h after initial contact between cement and water. Subsequent tests should be made at 1⁄2- to 1-h intervals. For concrete mixtures containing accelerators, or at temperatures higher than laboratory, it is advisable to make the initial test after an elapsed time of 1 to 2 h and subsequent tests at 1⁄2-h intervals. For concrete mixtures containing retarders, or at temperatures lower than laboratory, the initial test may be deferred until an elapsed time of 4 to 6 h. In all cases, time intervals between subsequent tests may be adjusted as necessary, depending upon the rate of setting, to obtain the required number of penetrations. d. Make at least six penetrations for each time-of-setting test, with time intervals of such duration as to provide a satisfactory curve of penetration resistance versus elapsed time. Continue testing until one at least penetration resistance reading equals or exceeds 4000 psi [27.6 MPa].
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e. Plotting Test Results — One of the following alternative procedures may be used to plot the test results and obtain times of setting. e.1. Use the following plotting procedure to determine the times of setting by hand-fitting a smooth curve through the data. Prepare a graph of penetration resistance, as the ordinate, versus elapsed time, as the abscissa, using a scale such that 500 psi [3.5 MPa] and 1 h are each represented by a distance of at least 1⁄2 in. [15 mm]. Plot the values of penetration resistance as a function of elapsed time. e.2. Use the following plotting procedure to determine the times of setting by linear regression analysis of the logarithms of the data by using a suitable calculator. Using log-log graph paper, prepare a graph of penetration resistance, as the ordinate, versus elapsed time in minutes, as the abscissa. The limits of penetration resistance on the ordinate should extend from 10 psi [0.1 MPa] to 10 000 psi [100 MPa], and the limits of elapsed time on the abscissa should extend from 10 to 1000 min. If slow setting mixtures are used, the time limits may have to be 100 to 10 000 min. Plot the values of penetration resistance as a function of elapsed time. e.3. Use the following procedure if a computer is used to plot test results and obtain the times of setting by regression analysis of the data. As the test results are obtained, enter the time and penetration resistance into the computer and plot the penetration resistance as the ordinate and the elapsed time as the abscissa. For software that permits only linear
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regression analysis, convert the data by taking their logarithms. The converted data will be fitted by a straight line7 (see Eq 1): Log (PR) = a + b Log (t)
equation (1)
where: PR = penetration resistance t = elapsed time a and b = regression constants The data do not have to be converted if the software permits direct fitting of a power function: PR = ctd
equation (2)
where: c and d = regression constants e.4. The procedures in 9.5.2 and 9.5.3 assume that the data obey (Eq 1) or (Eq 2). Verify that the data obey one of these relationships. If the correlation coefficient for the regression analysis, after removal of outliers is less than 0.98, use the procedure in e.1. 5. Curing of mortar cement specimens a. Carefully remove specimen from mold
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b. Place it inside the curing tank filled with water and wait until the desired curing period is reached c. Remove specimen from curing tank and prepare for compressive testing 6. Conducting the compressive strength test for the specimens a. Place specimen in the testing machine b. Load to rupture c. Record the maximum pressure the specimen reached before breaking 3.3 Research Instruments
1. Containers for Mortar Specimens 2. Penetration Needles 3. Loading Apparatus 4. Tamping Rod 5. Pipet 6. Thermometer 7. Curing Tank 8. Universal Compressive Testing Machine
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3.4. Gantt Chart
In order to know how long this study will last, the researchers made a chart that shows the activities that they may perform in each month as shown in Table 3.1.
t r a h C t t n a G 1 . 3 e l
b a T
