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Oyster and Mussel Shells as Partial Replacement for

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Junah John Tabinas

on 25 October 2013

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Transcript of Oyster and Mussel Shells as Partial Replacement for

Oyster and Mussel Shells as
Partial Replacement for
Coarse Aggregate in Concrete

The intensive use of construction aggregate in construction projects is severely increasing knowing that aggregates do not propagate by themselves, and transported haul granitic chippings are at high cost for distant sites. On the other hand, owing to the consumption of shell fish and the disposal of the non-edible shells, waste shell abounds. They pollute the land and water when discarded indiscriminately.
Quarries, which are now used throughout the world, use modern blasting methods having an impact with the environment:

Negative impacts in the environment involves the following:

-Risk of excess soil being eroded down from the quarrying site

-Loss of habitat for some fauna and flora species and biodiversity reduction due to vegetation clearing of the site

. (Green World Consultants, 2011)
The global market for construction aggregates is expected to increase 5.2 percent per year through 2015 to 48.3 billion metric tons.
The global market for construction aggregates is expected to increase 5.2 percent per year through 2015 to 48.3 billion metric tons.
Despite projected growth of 7.1 percent per year over this span, these products will continue to play a small role in world markets due to quality concerns and limitations in the availability of feed material. (World Construction Aggregates, 2012)
While in the Philippines, The total number of new construction projects from approved building permits nationwide reached 30,614 during the second quarter of 2012

This also indicates an increase for demand of construction aggregates in the Philippines, despite the fact that the country bears limited resources. (National Statistics Office, 2012)
A lot of oyster shells and mussels shells are dumped as a by-product of marine aquaculture industry. A large amount of oyster shells is a general waste fishermen should take care of but it seems difficult to handle it effectively due to the problems of securing of landfill sites and collection/transportation of oyster shells. (Farm Aquaculture Resource Management, 2007)
The waste shells are thrown away, which causes environmental problems:

-including pollution of coastal fisheries
-management problem of public water surface
-damage of natural landscape
-health/sanitation problem

(Department of Environment and Natural Resources, 2003)
Large majority of civil engineering construction companies in the Philippines uses granitic chips that are generally obtained by crushing deposits of granite at quarries. Unfortunately, the quarries are found only in a few localities, from where the granitic chippings are bought and hauled at high cost to various construction sites across the country. This greatly increases the cost of procuring concrete. (Philippine Statistical Yearbook, 2012)

Accordingly the high cost of hauled and transported granitic chippings as coarse aggregate and degradation of the natural resources causing a shortage of raw materials support the search for alternative materials as to waste seashells ample in Philippines. Thus, efforts must be done not only for recycling but also for the development of large-scale production materials in attempting to avoid large amounts of waste, especially mineral waste.
This study proposes a method of utilizing sea shells from consumption wastes and aquaculture industry shell wastes particularly oysters and green mussels (Perna viridis) shells as partial replacement for coarse aggregate in concrete.
Accordingly the high cost of hauled and transported granitic chippings as coarse aggregate and degradation of the natural resources causing a shortage of raw materials support the search for alternative materials as to waste seashells ample in Philippines. Thus, efforts must be done not only for recycling but also for the development of large-scale production materials in attempting to avoid large amounts of waste, especially mineral waste.
General Objectives:
• The study aims to examine the use of waste oyster and green mussel shells in the Philippines incorporated into a concrete mix as a partial coarse aggregate replacement that aim to reduce the storage of shell waste as well as quarried coarse aggregates

Specific Objectives:

• To design the specimen and proportion the concrete elements
• To determine whether the concrete produced from different percentages of shells will fall under lightweight concrete or normal weight concrete.
• To determine the compressive strength of concrete from different percentages of shells in 7, 14 and 28 days of curing.
• To ascertain whether concrete from different percentages of shells will meet the minimum required compressive strength

• Philippine oysters (talaba) and green mussels (tahong) will be examined to determine whether they are effective as partial replacement for coarse aggregates in concrete.
• It will not cover the utilization of seashells to fully replace the coarse aggregates in concrete.
• Focus on testing the different percentages of seashells as coarse aggregate replacement in concrete.
Oyster and Mussel shells are two of the commonest shell fishes in the Philippines. Disposal of the non edible shells abounds the coastal cities of Philippines. They pollute the land and water when discarded indiscriminately
Utilizing them as partial replacement of coarse aggregate in concrete could solve the problem of disposal. Thus, reduces the storage of shell waste, also reducing the need for quarried aggregate and has potential benefits of adding a different material to a design concrete mix.
The term seashell usually refers to the exoskeleton of an invertebrate (an animal without a backbone).
Study of molluscan animal is known as malacology; a person who studies mollusks is known as amalacologist.
The shell is generally composed of calcium carbonate

The upper surface of the shell is formed by tissue at the mantle edge, while inner layers are secreted by all parts of the mantle surface
Parallel to the edge allows for growth in size, and at right angles of the surface, producing growth in thickness
snails, clams, oysters and many others three distinct layers and are composed mostly of calcium carbonate with only a small quantity of protein--no more than 2 percent.
California Cone
Sand Dollar
Mussel Shells

One of the promising uses of waste seashells is in civil construction as
substitute for aggregates (chippings) especially in the coastal areas where these materials are lacking. Few researchers have conducted exploratory studies on the partial or total substitution of waste sea shells with coarse aggregates/chippings for the production of mortar and concrete used for civil construction.

Oyster Shells

Concrete is a composite material composed of coarse granular material embedded in a hard matrix of material that fills the space among the aggregate particles and glues them together.

Composition of Concrete There are many types of concrete available, created by varying the proportions of the main ingredients below. In this way or by substitution for the cementitious and aggregate phases, the finished product can be tailored to its application with varying strength, density, or chemical and thermal resistance properties.
Aggregate consists of large chunks of material in a concrete mix, generally or crushed rocks such as limestone, or granite, along with finer materials such as sand.

Cement . It is a basic ingredient of concrete, mortar and plaster.

Water Combining water with a cementitious material forms a cement paste by the process of hydration. The cement paste glues the aggregate together, fills voids within it, and makes it flow more freely.A lower water to concrete ratio yields a stronger, more durable concrete, while more water gives a freer-flowing concrete with a higher slump.

Aggregates Fine and coarse aggregates make up the bulk of a concrete mixture. Sand, natural gravel and crushed stone are used mainly for this purpose. The presence of aggregate greatly increases the durability of concrete above that of cement, which is a brittle material in its pure state.

Hydration and hardening of concrete during the first three days is critical. Abnormally fast drying and shrinkage due to factors such as evaporation from wind during placement may lead to increased tensile stresses at a time when it has not yet gained sufficient strength, resulting in greater shrinkage cracking.

Exploratory Study of Periwinkle Shells as Coarse Aggregates in Concrete Works
Cockle Shell: A Potential Partial Coarse Aggregate Replacement in Concrete

Making concrete tiles from Philippine oysters and mussels shells

Oyster and mussel shells are non-biodegradable. They pollute the land and water when discarded indiscriminately. Using them as raw materials for concrete tiles could solve the problem of disposal. The procedures and formula in making concrete tiles from marble dusts, chips and white cement were followed for oyster and mussel shells. Ground oyster and mussel shells were mixed separately with white cement on a 1:1 ration. The mixture was compressed on a mold. after drying, the finished products showed acceptable color and texture comparable to commercial concrete tiles.
Compressive strength of the tiles exceeded the required 28-day strength. Cost of production was minimal. (C.I Repil, 1993)

Standard Practice for Making and Curing Concrete Test Specimens in The Laboratory (C 192/C 192M – 02)

This practice covers procedures for making and curing test specimens of concrete in the laboratory under accurate control of materials and test conditions using concrete that can be consolidated by rodding or vibration (ASTM, 2009)

Cylindrical Specimens—Cylinders for such tests as compressive strength, Young’s modulus of elasticity, creep, and splitting tensile strength may be of various sizes with a minimum of 2-in. [50-mm] diameter by 4-in. [100-mm] length. Where correlation or comparison with field-made cylinders (Practice C 31/C 31M) is desired, the cylinders shall be 6 by 12 in. [or 150 by 300 mm].

Preparation of Materials



Mixing concrete

General — Mix concrete in a suitable mixer or by hand in batches of such size as to leave about 10 % excess after molding the test specimens. Hand-mixing procedures are not applicable to air-entrained concrete or concrete with no measurable slump.
Slump — Measure the slump of each batch of concrete immediately after mixing in accordance with Test Method C 143/C 143M

Initial Curing
Removal from Molds
Curing Environment
Standard Test Method for Density (Unit Weight) of Concrete

This test method covers determination of the density of freshly mixed concrete and gives formulas for calculating the unit weight.(ASTM. 2009)
Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens (C39/C39M – 10)

This test method consists of applying a compressive axial load to molded cylinders or cores at a rate which is within a prescribed range until failure occurs.
(American Society for Testing and Materials, 2009)

Testing Machine

Placing the Specimen
Zero Verification and Block Seating
Rate of Loading
acquiring density or unit weight of concrete
specifications and formula
for compressive strength
Designing the Specimen
Determine the Dimensions of the Cylindrical Specimen
Determine the Size of Aggregates
Determine the Proportion of concrete elements
Calculating the Bulk Density
Density= (M(net)-M(emp))/Vol
Calculating the Compressive Strength
Results and Discussions

Corresponding from standard methods and testing, with the evaluation of the gathered data, and upon interpreting the results, the researchers have concluded the following:

1.) The concrete produced by partially replacing granitic chippings with oyster and mussel shells are all lightweight concrete. Therefore beneficial for coastal areas with low bearing capacity.
2.) 25% oyster and mussel shell replacement met the minimum required compressive strength of 17Mpa. Higher percentage of shell replacements as for 50% and 75% would not be suitable for making a sound concrete

3.) Compressive strength and density of concrete increases as the percentage of oyster and mussel shells decreases

The following are the recommendations suggested by the researchers themselves upon completion of the study for further development and improvements:

1.) Integrate an economic study or a cost analysis reduction for shell replacement of coarse aggregate in concrete.
2.) Utilize the use of Volume method in concrete batching
3.) Increase the number of level of oyster and mussel shells replacement in concrete as well as the mix ratios for a more accurate outcome.
4.) Further research should be conducted concerning absorption of oyster and mussel shells affecting the porosity of concrete produced from partial shell replacement of granitic chippings.
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