Development Of An Improved Concrete Roman Tile Alternative Roofing System Using Waste Raw Materials (Paper & Saw Dust) As Additives
Adegoke, C. W., Abiodun Funmi
Keywords: alternative building materials, roofing systems, concrete tiles, local raw materials, weight reduction.
ABSTRACT: Since the early civilizations in China (Neolithic) and the Middle East, humans have recognized the dual desirable roles of clay tiles, as roofing material, which remain valid today - First, it was an effective means to shed water from buildings and secondly it reduced the spread of fire. The Standard Double Roman tile (SDRT) was the first roof tile to be mass produced in South Africa. The Double Roman can trace its shape back to Roman engineering principles where it was discovered that arches have an ability to withstand greater pressures as the arch distributes the weight more evenly down to the base of the structure. However, after the initial introduction of the concrete tile to Nigerian roofing market, architects began to express displeasure with its unusually heavier weight than other competing roofing materials. Suggestions were made to original manufacturers for product improvement by reducing the overall product weight. Concrete tiles are composite materials made from mixture of Portland cement, sharp sand, smooth sand and natural fibre. Bolyn Industries  has established that a mix ratio by volume of 1(cement):11/2(sharp sand):11/2(smooth sand) with some fibre makes a good concrete tile product. The sharp sand provides strength while smooth sand provides smoothness to the concrete surface. This study seeks to improve the current Double Roman product by reducing its overall product weight which is currently at about 5.0 kg to about 4.0 kg. Going by the previous experience with Polycrete invention , it is hereby conceived that replacement of smooth sand with lighter waste materials such as paper or saw dust in the concrete tile constituents may achieve the desired product weight reduction. The study investigates the most economic mix ratio of the concrete tile constituents to achieve the desirable engineering properties of light weight, strength, durability, water tightness and rust-proofness. Results with preliminary mix trials indicate that replacement of smooth sand with paper or sawdust in the concrete batch may achieve the desired results, but paper produces a better ductile and more workable material while saw dust produces a brittle and more crack-prone product. It is established in this study that 16-18 Products of Improved Double Roman Roofing Tiles (IDRT) of approximately 4.2kg each, are achieved in a batch mix of 1 head-pan of Portland cement, 2 head-pans of sharp sand and 4kg of waste paper compared to the average weight of 5.0kg achieved for the Standard Double Roman Tile (SDRT). Comparative market survey of existing roofing systems in Nigeria shows that there is a wide range in cost of N450.0 per m2 for Galvanized Iron sheet, N1500.00 per m2 for Aluminium Long span and N3,500.0 per m2 for Classic Stone-Coated roofing sheets respectively compared to N1000.0 per m2 achieved for the IDRT; thus the second objective of this study to achieve a competitive product price in the median of the above-reported cost range has also been achieved.
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 Professor & Former Director, Centre for Alternative Energy Research & Rural Environmental Technologies (CAERRET), Osun State University, Osogbo
 Final Year Student, Civil Engineering Department, Osun State University, Osogbo.