Use of crushed oyster and mussel shells as an alternative coarse aggregate in the production of concrete / by Khim Adrian M. David and Jhinelle Mae P. Tadlip.

Thesis (Bachelor of Science in Civil Engineering) Cavite State University.

Includes bibliographical references.

College of Engineering and Information Technology (CEIT), Department of Civil Engineering

DAVID, KHIM ADRIAN M., and TADLIP, JHINELLE MAE P. Use of Crushed Oyster and Mussel Shells as an Alternative Coarse Aggregate in the Production of Concrete Undergraduate thesis. Bachelor of Science in Civil Engineering. Cavite State University, Indang, Cavite. May 2017. Adviser : Engr. Cene M. Bago

The study was conducted to determine the use of crushed oyster and mussel shells as an alternative coarse aggregate in the production of concrete. Specifically, it aimed to determine the physical and chemical characteristics of oyster and mussel shells; establish the compressive strength of concrete from different proportions of crushed shells in 7, 14 and 28 days curing periods; determine whether the concrete produced from different percentages of shells will fall under lightweight concrete or normal weight concrete

Oyster and mussel shells were collected from Noveleta and Cavite City, Cavite. It was cleaned, sun-dried, crushed and then sieve to provide 4” to “4” size of aggregates. Different trial mixes for slump and compression strength test were weighed and tested. The trial mixes were 100% - 0%, 75% - 25%, 50% - 50%, 25% - 75%, 0% - 100% gravel—crushed oyster and mussel shells ratio.

Crushed oyster and mussel shells used as an alternative coarse aggregate weights result ranges from 697.22 kg/m* to 590.56 kg/m® and were proven to produce a lightweight low density concrete which rarely exceeds 800 kg per cubic meter. It is used to reduce the dead load of a concrete structure but not advisable to be used in structural members like columns, beams and slab, however, it can be used in some construction works like, paths walks and lean concrete.

The most economical mix proportion was T2 (75% gravel-25% crushed oyster and mussel shells). The mixture costs P 308.18 compared to the costs of normal concrete which was P 336.55. T2 attain the highest compressive strength which is 11.9 Mpa or 1725. 95 psi among the mix proportions with the combination of oyster and mussel Shells. It was the nearest mixture that almost attained the minimum required strength which should be 20.68 Mpa or 3000 psi. .

Physical characteristics include the distinctive oblong shape of mussel shells while oyster shells have varying shapes that depends on the family where they belong.

The absorption properties of mussel and oyster shell are respectively 50.65g and 90g per 100g of water. Chemical properties revealed that oyster shells has 95.99 % and mussel shells has 98.37 % of Calcium Carbonate (CaCO3) and has the highest percentage from both sea shells among all the chemical compounds. It also shows that there was an evidence of salts for every sea shell under this study.

The researchers recommend the use of crushed oyster and mussel shell in producing lightweight low density concrete. Oyster and mussel shells can be used for concrete pavement for lightweight vehicles, path walks and lean concrete. It can also be utilized for landscaping purposes since shells have a good aesthetics quality.

Submitted to the University Library November 21, 2017 T-7280