Calcined mussel shells in lightweight concrete roof tiles with pumice as partial fine aggregates/ Victorino Jr Ds. Calizo, Christian P. Gomez, Paula B. Repatacodo, Franchesca L. Rodriguez, and George N. Tabobo.--

Bachelor's thesis

College of Industrial Technology.-- Bachelor of Engineering Technology major in Construction Technology: Technological University of the Philippines: 2025.

Includes bibliographic references and index.

Pumice and calcined mussel shells (CMS) are abundant, sustainable materials with
promising applications in construction. In the Philippine context, pumice is readily
available from volcanic sources, while mussel shells, rich in calcium carbonate, are an
underutilized byproduct of the aquaculture industry. Conventional concrete roof tiles are
often heavy, posing challenges in transport, installation, and structural support. This study
sought to develop lightweight concrete roof tiles by partially replacing sand with pumice
and incorporating CMS as a supplementary cementitious material to enhance strength. Five
mix designs were formulated using a cement-to-fine aggregate ratio ranging from 1:3 to
1:1.5, and a constant water-cement ratio of 0.45. All mixes maintained a consistent amount
of sand while varying the proportions of pumice and CMS. The roof tiles were cast, cured
for 28 days, and evaluated based on dimensional tolerance, transverse strength, and water
absorption in accordance with ASTM C1492 standards. The results indicated that
increasing pumice content effectively reduced the weight of the tiles, achieving a
lightweight classification. Meanwhile, CMS contributed to improved mechanical strength
up to an optimal level. Among the designs, Mix 5 demonstrated the best performance,
striking an ideal balance between reduced weight and structural integrity. Additionally, the
prototype was assessed using the TUP Instrument Evaluation Form by 30 professionals
and students, receiving an overall mean rating of 4.48, classified as “Very Acceptable.”