Feasibility of Mussel Shells in Making Hollow Blocks Arceo, Chester Lim, Kyle Mabasa, Jojo Marquez, Avery Sonza, Ethan Lourdes School of Mandaluyong St. Ignatius of Laconi Armand John Yangat February 22, 2013
DEDICATION This study is dedicated to people who have curious minds that could devote their time, body, mind, money, and heart for the sake of Science and for the sake of the improvement of civilization. This study is also aimed for the sake of the pr ominent minds and bright futures of the future students of Lourdes School of Man daluyong. This study is also dedicated to the researchers' prominent, outstanding, inspirati onal Physics teacher, Sir Armand John Yangat for being their light and guide in conducting the research. i i i
ACKNOWLEDGEMENT The researchers express their utmost gratitude to their Physics teacher, Sir Arm and John Yangat, for giving them the opportunity to conduct this experiment and for the support, encouragement, patience and perseverance he portrayed. Sir Yang at is, indeed, a true inspiration and role model to society. The researchers wou ld also like to thank the people who have had helped them in conducting, researc hing and printing the experiment and research such as the parents of the researc hers for providing the materials, mainly the mussel shells, the High School Libr ary of Lourdes School of Mandaluyong for providing useful and detailed informati on related to the research, the University of the Philippines Institute of Civi l Engineering for providing past, similar, researches and for testing the compon ents of the hollow blocks. Lastly but certainly not the least, the researchers w ould like to thank the people who have whole-heartedly read, studied and used th is research for the greater good of the world. ii
ABSTRACT This study aims to develop with stronger and tougher hollow blocks by the means of adding mussel shells to the base composition of the hollow block so that it c ould withstand greater compressive strength. This will also serve as a substitut e for the regular, commercial hollow blocks that are deemed quite expensive in t he current market. Based on initial research, the researchers believe that musse l shells, or rather a crustacean shell, can offer extra strength and durability when used properly hence, leading to mussel shells used as an additive in hollow block making. The study is mainly for the betterment and improvement of civiliz ation by killing two birds with one stone: addressing the pollution and solid wa ste problem by recycling mussel shells and by improving infrastructures by stren gthening the foundations of it through improving the base which, in the Philippi nes, is usually hollow blocks integrated with the famous cooking thought: Better ingredients, better food. iii i i
TABLE OF CONTENTS Dedication - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - i Acknowledgement - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ii Abstract - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - iii Table of Contents - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - iv Chapter I: Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1-4 Background of the Study - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 Statement of the Problem - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 Hypothesis of the Study - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 Significance of the Study - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 Scope and Limitatio ns of the Study - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 - 4 Defi nition of Terms - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4 Chapter II: Review of Related Studies and Literature - - - - - - - - - - - - - - - - 5 - 9 Chapter III: Methodology - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Research Design - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Sampling Procedure - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10 11 11 Instrumentation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11 Research Procedure - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11 - 12 Research Diagram - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12 Chapter IV: Presenta tion, Analysis and Interpretation of Data - - - - - - - - - 13 - 14 Chapter V: Summary, Conclusion and Recommendation - - - - - - - - - - - - - - 15 - 16 Summary - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15 Conclusion - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15 - 16 Recommendation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Bibliography - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 16 v iv
CHAPTER I INTRODUCTION Background of the Study The world progresses alongside civilization, culture and technology; innovation is a must. As part of human nature, man continues to make life easier through inventions, discoveries and innovations hence, the assurance of the best possibl e service and materials available for the daily lives of man. As an attempt to innovate , the researchers have decided to commit ourselves to a research that w ill do just that. An experiment revolving around a common building tool used in almost every infrastructure around the world: hollow blocks. Hollow blocks are large rectangular bricks used in construction. It is a basic b uilding tool. It is also known as concrete blocks, cement blocks and as foundati on blocks. These are made in several different ways such as, in Portland, cement and either sand and fine gravel aggregates for high density-blocks or industria l wastes for low density-blocks. Those that use cinders -fly ash or bottom ashare called cinder blocks in Canada, the US and New Zealand, breeze blocks -breez e is a synonym of ash- in the UK. Hollow blocks in the Philippines and are also known as besser blocks or bricks in Australia. Clinker blocks use clinker as agg regate. In non-technical usage, the terms cinder block and breeze block are ofte n generalized to cover all of these varieties. Lightweight blocks can also be pr oduced using aerated concrete. Several environmentalist groups, researchers and students has had experimented o ver the matter of what additive is suitable to increase the effectiveness of hol low blocks wherein lime soil, coconut coir, rice hull, plastic and a few others were used as an additive. This, 1
however, did the opposite wherein the hollow block became less solid , making i ts building options lesser for instance, walls and fences were the only stable p roducts. After initial research, the researchers stumbled upon a common product that coul d strengthen materials with its high calcium carbonate that will supposedly stre ngthen cement. Mussel shells, the common product, are considered waste for it is usually thrown out immediately after consumed. Mussel shells contain 95-99% cal cium carbonate by weight, while an organic component makes up the remaining 1-5% . The resulting composite has fracture toughness ~3000 times greater than that o f the crystals themselves. In the biomineralization of the mollusk shell, specia lized proteins are responsible for directing crystal nucleation, phase, morpholo gy, and growths dynamics and ultimately give the shell its remarkable mechanical strength. The application of biomimetic principles elucidated from mollusk shel l assembly and structure may help in fabricating new composite materials with en hanced optical, electronic, or structural properties. Statement of the Problem How will mussel shells used as an additive affect the h ollow block s compressive strength? Would the ratio of sand to mussel shells aff ect it? o o o 40% Mussel Shells while 60% Sand 50% Mussel Shells while 50% Sand 60% Mussel Shells while 40% Sand
Will a commercial hollow block be better than the home-made hollow block with mu ssel shells as an additive in terms of compressive strength? 2 i i
Hypothesis of the Study There is no significant difference in the feasibility of the hollow block based on the amount of mussel shell-additives with the commercial hollow block. Significance of the Study The chosen study, Feasibility of Mussel Shells in Making Hollow Blocks, can help the society in its crisis in solid waste management because with the help of th is study, the researchers can reuse the shells as an additive instead of simply disposing them. This study can also help the construction industry in producing more efficient and stronger hollow blocks. Stronger hollow blocks would mean a b etter, more reliable foundation for infrastructures such as houses, buildings, b ridges, towers and the like. This would also benefit the economy due to the geog raphical feature of the Philippines wherein it is surrounded by water, making th is, if successful, an easier and more common way to produce better hollow blocks . Ecology-wise, this would also beneficial due to the reuse of empty mussel shel ls because mussel shells are not easily decomposed. Burning these will harm the atmosphere, environment and the people. Scope and Limitations of the Study The study was formulated to determine if using mussel shells as an additive to h ollow blocks would either make the hollow block stronger or weaker. The research would have four set-ups; one commercial hollow block and three with mussel shel ls as an additive but with different amounts of mussel shells and sand; 40-60, 5 0-50 and 60-40 respectively. 3
The limitation of the study is that the researchers will not conduct the experim ent inside the school, but rather outside of its premises hence, the hollow bloc k would be homemade. The study cannot be successful without seeking professional help due to the fact that compressive strength needs to be determined through t horough laboratory analysis. The study will be tested at the University of the P hilippines Institute of Civil Engineering. Additionally, the research is only l imited in determining the compressive strength of the hollow blocks, making the conclusions and interpretations of this experiment solely based on the PSI. Any form of building shall not be used either. Definition of Terms cement. a building material made by grinding calcined limestone and clay to fine powder, which can be mixed with water and poured to form a solid mass; used as an ingredient in making mortar or concrete compressive strength. maximum stress a material can sustain under crush loading hollow block. concrete or burnt clay hollow blocks used for construction of hollow-tile floors mussel. any of various marine bivalves of the genus Mytilus and related genera especially medulis. edi ble mussel; having a dark, slightly elongated shell and, usually, attached to ro cks psi. a unit of pressure or of stress based on avoirdupois units. It is the p ressure resulting from a force of one pound-force applied to an area of one squa re inch ultimate load. a statistical figure of the maximum weight a substance ca n withstand 4
CHAPTER II REVIEW OF RELATED LITERATURE AND REVIEW OF RELATED STUDIES This chapter deals with the concepts, research studies and literature of the stu dy. The concepts are organized around major topics that are derived from the var iables that have been explained in the study. Concrete blocks are made from cement and aggregate blocks. They are cheaper and more utilitarian than traditional clay bricks. They are often used for retaining walls and garden screens, although some blocks that mimic the colour and textur e of store are widely used for dwellings. A mussel is any bivalve mollusk, especially and edible marine bivalve of the fam ily Mytiliadae and a freshwater clam of the family Unionidae. The byssal threads of the mussel are so adhesive that they even cling to Teflon; scientists are no w trying to develop a mussel-based adhesive for use in eye surgery. The oyster c reates its own environment by secreting a shell composed or ninety-five percent (95%) of calcium carbonate. The remainder of the shell is made up of organic mat erial and trace amounts of manganese, iron, aluminum, sulfate and magnesium. The structure or the shell of a mussel consists or four distinct layers: periostrac um, a tissue of organic material called conchiolin, secreted by the cells locate d near the edge of the mantle. The periostracum is poorly developed in crassostr ea virginica and it is not round in old shells, prismatic layer, which is made u p of bricklike prism units. Each prism consists or calcite crystals laid in a ma trix of conchiolin. The conchiolin can be destroyed by boiling in potassium hydr oxide and the prisms are separated, calcite-ostracum is a subnacreous layer cons isting or foliated sheets or calcite laid between thin membranes of conchiolin. This layer is interrupted by 5
soft chalky deposits which consist of amorphous material. This layer makes up th e major part of the shell, hypostracum layer is made or shell material under the abductor muscle. In the crassostrea virginica the layer is pigmented and consis ts of aragonite. As the oyster grows the adductor muscle increases in size and t he new areas or attachment become covered with aragonite. Shells grow by the accretion of material secreted at their edges. The rings on t he outer surfaces or a bivalve shell represent the contours of the shell at diff erent ages. Rings are common to all bivalves' shells. Depending on the shape of th e shell, the rings are either circular or oval with a common point or origin at the extreme dorsal side near the umbo. The rate of growth along the edge of the shell is not uniform and may actually change direction in response to environmen tal factors The mantle of the mussel; the animal inside the shell is covered by a mantle. Th e principal function of the mantle is the formation or the shell and its calcifi cation. It is made up of soft and freshly tissue. The structure of the mantle co nsists of a sheet of connective tissue containing muscles, blood vessels, nerves and it is covered on both sides by epithelium. The mantle receives sensory stim uli, and conveys them to the nervous system and aid in the shedding and dispersa l of eggs. It also participates in respiration, stores reserve materials, secret es large quantities of mucous and aids in excretion. The most obvious components of the mantle are the radial muscles, blood vessels and nerves. The radial musc les are large bands of fibers which extend almost the entire width of the mantle . The radial muscle contracts and pulls the entire mantle inside and throws its surface into ridges. The mantle's blood vessel are the circumpallial artery which sends out many branches; the common pallial artery, and a large pulsating vessel in the anteriorventral part of 6
the mantle called the accessory heart. The nerve provides communication. Close n erve contact is maintained between the muscles and the organs of the mantle thro ugh a fine nerve network. An important use of calcium carbonate is in the building industry. Due to its wi de abundance and properties, it has been used as a building substance since anci ent times. For example, the Egyptians used limestone for building their pyramids . Another notable monument made up of white marble is the Taj Mahal in India. To day, calcium carbonate is used in construction of buildings, roads and other eng ineering works. Besides construction, calcium carbonate is also used in other industries like pa int, plastic, rubber, ceramic, cement, glass, steel, oil refining, iron ore puri fication and biorock creation for mariculture of sea organisms. It is used as a blackboard chalk and as pH correcting compound in swimming pools. As per statist ics, about 200 tons of chalk is used every year. Calcium carbonate is the most p referred mineral in the paper industry, used for filling and coating paper. It h elps in production of the best quality printing papers. Since calcium is essential for healthy bones and teeth, calcium carbonate is use d as dietary calcium supplement. Calcium carbonate supplement is effective to tr eat certain ailments related to calcium deficiency, for example, osteoporosis an d acidity problems. Calcium supplements, made from calcium carbonate, are prescr ibed in various doses as per the requirement of the patients. Calcium carbonate is used in homeopathy, production of toothpaste and as an inert substance in tab lets. Calcium carbonate is a primary component of garden lime, also known as agricultu ral lime, which is used for neutralizing soil. Acidic soils can be treated with garden lime to enhance 7
the soil quality. Garden lime when added in soil acts as a calcium source for pl ants as well as increases the pH and water retaining capacity of acidic soils. C alcium carbonate sources such as limestone and chalk, along with other chemical compounds are used in preparation of garden lime. Calcium carbonate has various environmental applications. It is used in the trea tment of drinking water, desulphurisation of flue gas and waste water treatments . Water bodies affected by acid rain can be neutralized by using calcium carbona te. However, care has to be taken as it can increase the concentration of alumin um ions. Compressive strength is the capacity of a material or structure to withstand axi ally directed pushing forces. It provides data (or a plot) of force vs deformati on for the conditions of the test method. When the limit of compressive strength is reached, brittle materials are crushed. Concrete can be made to have high co mpressive strength, e.g. many concrete structures have compressive strengths in excess of 50 MPa, whereas a material such as soft sandstone may have a compressi ve strength as low as 5 or 10 MPa. By contrast, a small plastic container might have a compressive strength of less than 250 N. Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime, and is usually the prin cipal cause of hard water. It is commonly used medicinally as a calcium suppleme nt or as an antacid, but excessive consumption can be hazardous. 8
Ms. Frances Monina M. Obrero's study, according to investigatoryprojectexample.com , focused on the possibility of replacing silica in ceramic production with oyst er shells. Powdered oyster shells were used instead of silica in the production of ceramics. The texture, color and durability of the ceramics were compared to those made with silica. Six kilograms of Vigan clay and 2.5 kg of ball clay were mixed and soaked in water overnight. The following day, the mixture was kneaded again and filtered. The mixture was placed over Plaster of Paris for the water to be absorbed. The solidified mixture was then rolled and compressed to let the air escape from the spaces inside the solidified mixture. After this, the mixture was molded, a ir dried for four days and fired in a furnace. Three trials were made at differe nt temperatures ± 900 degrees Celsius, 950 degrees Celsius and 1000 degrees Celsiu s. The finished products were compared in terms of texture and color to those ma de using silica. Ten evaluators from the staff of the University of Northern Phi lippines ± Ceramics Research, Training and Development Center rated set-ups in a s cale of 1-10 with 1 being the lowest rating and 10 the highest. It was found tha t the texture of the experimental set-up is better than the control set-up. It w as also found that the color of the experimental set-up is comparable to the con trol set-up. Tests on durability of the ceramics, which were done at SLU College of Engineering Laboratory, revealed that the experimental setup is more durable than the control set-up. This proves that oyster shell can be utilized in the p roduction of ceramics. It also affirms that ceramics made using oyster shells ar e better than those produced using silica in terms of texture and durability. 9
CHAPTER III METHODOLOGY The study used the experimental method of research. In this kind of research the investigations manipulate the experimental variables. Research Design Dependent Variable Independent Variable Constant Variable
Compressive Strength of the Hollow Block
Amount of Mussel Shell Additives
Amount of Cement Amount of Water Dried Mussel Shells Size of the Hollow Block (M old)
Amount of Sand Additives
Ultimate Load Quality of the Hollow Block Table 1.1. Table of Variables The experimental method is used to determine the relationship of the variables w herein the dependent variable would be the compressive strength of the hollow bl ock, the ultimate load and the quality of the hollow blocks while the independen t variables would be the amount of mussel shell additives and the amount of sand additives and the constant variables would be the amount of cement, amount of w ater, the dried mussel shells and the size of the hollow block depending on the mold or Tupper wear. 10
Sampling Procedure This part of the study briefly discusses the procedures in conducting the study. The follow steps were taken by the researchers to complete their study; first, they gathered all the required materials: a hammer, spatula, Tupper wear, mussel shells, sand and water, second; they sun-dried the shells then crushed them tho roughly, third; prepare the four set-ups. Testing would be done by people from t he University of the Philippines due to the researcher s lack of equipment. Thei r laboratory is a necessity and a must in this experiment. Instrumentation The researchers aim to make hollow blocks with mussel shells as an additive. To do so, several tools and materials are required such as: a hammer to crush the s hells; a weighing scale to measure the materials like sand, cement, mussel shell s; shovel, a spatula or a wooden rod for mixing substances and mixtures and; a T upper wear or any molding material to mold the hollow block. The study will be g oing to the University of the Philippines Institute of Civil Engineering for th e testing of compressive strength. Research Procedure This part of the study is a detailed procedure of the whole experiment. The gath ered mussel shells were sun dried for half a day on a sheet of foil. These were then crushed with the hammer. The set-ups were made by the people from the Unive rsity of the Philippines wherein the researchers only provided the materials. As recorded by UP, there were 4 set-ups: A, B, C and D. Set-up A was a commercial block; set-up B s additive composition had 60% mussel shells and 40% sand while; set-up C had 50% mussel shells and 50% sand and; set-up D with 11
40% mussel shells and 60% sand. They also claim that similar students has had do ne this exact request before, making it easier for them. The blocks were left to harden up and will be tested at their laboratories immediately after the comple ted hollow block making process. The laboratory tests would test the four blocks' compressive through pound force per square inch or PSI. The results would be sen t to the researchers for further analysis and interpretations that would lead to this experiment s conclusion. Research Diagram Gather the materials. Let the professionals do their thing. Conduct the experiment by... Testing its compressive strength. Clean the mussel shells. Bring them to the laboratory. Sun dry them for half a day. Flowchart 1.1. Procedure Crush them. Observe and record. 12
CHAPTER IV PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA Set-Ups Ultimate Load Compressive Strength 1.023 psi A Commercial Block 50,000 pounds B 60% Mussel Shells; 40% Sand 65,000 pounds 1.19 psi C 50% Mussel Shells; 50% Sand 54,500 pounds 1.089 psi D 40% Mussel Shells; 60% Sand 51,500 pounds 1.045psi Table 2.1. Table of Data As presented in the table, the results of the compressive strength test from the University of the Philippines tests is as follows: set-up A, the commercial bl ock, had an ultimate load of 50,000 pounds resulting to a 1.023 psi (Pounds per Square Inch) while; set-up B, 60/40, had an ultimate load of 65,000 pounds resul ting to a 1.19 psi; set-up C, 50/50, had a 54,500 pound load, leading to a 1.089 psi and; set-up D, 40/60, had the load of 51,500 pounds with the compressive st rength of 1.045 psi. As seen in the table and by analyzing the results, it is clear that the amount o f mussel shells does indeed affect the compressive strength of the hollow blocks and, as it seems, affects it in a more positive way wherein its compressive str ength is somewhat higher and better than 13
that of a commercial hollow block. Additionally, the ratio of mussel shells to s and also affects the results. As observed in the testing, the more mussel shells there is, the higher compressive strength and the less mussel shell there is, t he lesser the compressive strength. To emphasize and to clarify the interpreted data regarding the effects of the hollow block-to-sand ratio to the hollow block's compressive strength, refer to the presented graph below: Set-up B Set-up C Mussel Shells Sand Set-up D 0% 20% 40% 60% 80% 100% Table 1.1. Ratio of Mussel Shells to Sand Setup B Setup C Set-up D Set-up C Set-up B Setup D 0.95 1 1.05 1.1 1.15 1.2 1.25 Table 1.2. Compressive Strength of the Set-Ups with Mussel Shells 14
CHAPTER V SUMMARY, CONCLUSION AND RECOMMENDATION Summary of Findings The results from the conducted tests show that blocks with mussel shells as addi tives are indeed more effective wherein, considering the compressive strength an d the additional results of the ultimate load: Set-A, the commercial block, had an ultimate load of 50,000 lbs. with 1.029 psi while Set-B, having 60% mussel sh ells, had more than 15,000 lbs. ultimate load compared to Set-A. The results dee m that the compressive strength is directly proportional to the ultimate load he nce, as the ultimate load increases, the compressive strength does too. With tha t, comparing Set-C and Set-D respectively to Set-A: 4,500 lbs. difference with 1 .089 psi and 1,500 lbs. difference with 1.045 psi. Conclusion By observing the analysis, tests and summary of findings, the research's statement of the problem can be claimed that the percentage of mussel shells is directly proportional to the ultimate load which is also directly proportional to the com pressive strength hence, concluding that mussel shells used as an additive in ho llow block making does in fact make the hollow block's compressive strength greate r which can be basically summed up to: mussel shells additives increase the comp ressive strength of hollow blocks. As seen at the results of the tests, the amou nt of clam shells, particularly set-up B: the 60% mussel shell additive, is a cl ear result that more mussel shells would make the hollow block stronger in terms of compressive strength and ultimate load. Comparing it to set-up A: the commer cial hollow block, set-up B would 15
appear superior. Same goes to set-up C: 50% mussel shell additive and set-up D: 40% mussel shell additive in contrast with set-up A. These set-ups support the s tatement that the more mussel shell additive added to the hollow block would mak e the hollow block's compressive strength greater wherein these set-ups determined that the less mussel shell additives made the hollow block's compressive strength lower. Therefore, the conclusion: mussel shells used as an additive in hollow b lock making would make the hollow block stronger in terms of compressive strengt h and, additionally, ultimate load. Recommendation The researchers would like to recommend: planning ahead of time is highly recomm ended for the next batch of researchers for collecting a sizable amount of musse l shells poses to be an easy task but in reality, it is rather a tedious act. Ad ditionally, the testing laboratory at the University of the Philippines is highl y recommended for testing various quantities, qualities and compositions such as , in this experiment's case, ultimate load and compressive strength. However, plan ning the tests ahead of schedule would be, also, highly recommended due to the f act that the people at the University of the Philippines are quite busy; a sched uled appointment is a must. It is also recommended that instead of using mussel shells, several other additives may be used such as, as mentioned in the introdu ction, lime soil, coconut coir, rice hull, plastic or other Mollusks such clams, oysters, crabs, lobsters and the like. It is also recommended to, as the origin al plan of this experiment, try pure additives without the mix of others such as , in this case, sand; making the experiment only 100% mussel shells or 100% chos en additive which, by theory, should make the hollow block even stronger. Anothe r recommendation would be seeking professional help in making the hollow block t o secure the best and most accurate results, as did in this experiment. Proper t esting, however, would cost at least 2, 500 Pesos. 16
BIBLIOGRAPHY Journals: Reader's Digest (2005). Concrete and Clam Shells. Websites: Chemical Composition of a Mussel Shell (2009). Retrieved on October 17, 2012 acc essed http://answers.yahoo.com/question/index?qid=20090501145314AAMbNUF Uses of Calcium Carbonate (2002). Retrieved on August 22, 2012 accessed from http://www. buzzle.com/articles/uses-of-calcium-carbonate.html The Mussel (2002). Retrieved on August 23, 2012 accessed from from http://yale.edu/ynhti/curriculum/units/1985/7/85.07.02.x.html Calcium Carbonate (2004). Retrieved on August 22, 2012 accessed from http://www.famousminechem.com/calcite.htm Hollow Block (2003). Retrieved on Augu st 22, 2012 accessed from http://websters-online-dictionary.org/definitions/holl ow+block Mussel (2000). Retreived on August 22, 2012 accessed from http://thefreedictionary.com/mussel Cement (2000). Retrieved on August 22, 2012 accessed from http://thefreedictionary.com/cement Compressive Strength (2008). Retrieved on Ja nuary 27, 2013 accessed from http://www.matsc.ktu.lt/index.php/erem/article/view Article/42 Calcium Carbonate (2013). Retireved on January 27, 2013 accessed from http://en.wikipedia.org/wiki/Calcium_carbonate Ultimate Load (2013). Retrieved o n January 27, 2013 accessed from http://en.wikipedia.org/wiki/Ultimate_load Compressive Strength (2013). Retrieve d on January 27, 2013 accessed from http://www.instron.co.uk/wa/glossary/Compres sive-Strength.aspx Testing the Compressive Strength of Concrete. Retrieved on Ja nuary 27, 2013 accessed from http://www.nrmca.org/aboutconcrete/cips/35p.pdf v
