Use of foundry sand as a landfill cap layer material

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2015

Öğrenci: UTKU AKKAYA

Danışman: ERDAL ÇOKÇA

Özet:

A foundry is a kind of manufacture that generates metal castings by pouring molten metal into a preformed mold to yield the resulting hardened cast. Foundries buy specific and high quality silica sands which shape the outer form of mold cavity in casting and molding operations. These sands normally mixed with a small amount of bentonite in order to act as a binder material Landfill capping is a kind of containment technology that is kind of barrier between the contaminated media and the surface. Cap performance varies, for example, compacted clay liners are effective if they retain certain moisture content, but they are susceptible to cracking if the clay material is dried out. Consequently, alternate cap designs can be considered for liner design at arid environments. Within the scope of this thesis, use of foundry sand with some additives as a landfill cap layer material is examined. For this purpose, laboratory tests were performed with these samples: Foundry sand (For two different type of foundry sand: Green sand and Resin Bonded Sand) , Foundry sand+ Bentonite (various proportions), Foundry Sand+Bentonite+ Waste Rubber (with different shapes). vi Samples were compacted to their 95 % of o.m.c and dry density. The following tests; Index properties, oedometer test, permeability k, constrained modulus D, split tensile Strength, Direct Shear tests were carried out for each sample. It was found that increasing bentonite content (≥9 %) decreased the hydraulic conductivity below the requirements (10-9 m/s) for all foundry sand. Adding rubber (3 %) to foundry sand bentonite mixture, increases the split tensile strength for all types of samples, it also increased hydraulic conductivities and only 1 result was found below the requirements All these results showed that foundry sand with bentonite and rubber revealed good candidate for construction of a landfill cap layer material.