Improvement of engineering properties and liquefaction reduction of sandy soils using electric arc furnace slag and roof tile powder

The scarcity of suitable land for construction of engineering facilities and shortage of natural earth aggregates has highlighted the need for finding innovative way of construction. Nowadays problematic soils such as: soft clay, organic soils and liquefiable soils can be improved to the required civil engineering requirements by application of soil stabilization. Soil stabilization is a method intended to increase or preserve the stability of soil mass and chemical alteration of soil to improve engineering properties.
Generally, ground treatment techniques used are: densification, reinforcement, drainage and deep soil mixing. Using soil treatement, unbound materials can stabilized with cementitious materials (lime, cement, fly ash, waste materials). Replacement of stabilizing agents with waste materials is becoming a need due to lack of natural resources and environmental concerns. Slag a by-product of metallurgical industry is being used to improve engineering properties of low bearing capacity soils.
In this study, mechanical properties of non-cohesive soils are improved using waste materials. Waste material used is: electric arc furnace slag (EAF slag). Natural materials diatomite and roof tile powder are mixed too. In order to activate slag, some chemical additives were added. Firstly, cylindrical samples with different proportions were prepared. They were tested for period of 7, 21 and 28 days under unconfined compressive strength (UCS) test. The optimum mixture was tested also under 1-D shaking table subject to different earthquake records. Photogrammetric approach was used to observe behaviour of soil under dynamic load and settlement.
It was seen that combination giving the highest compressive strength was mixture containing EAF slag, sand, lime and sulphuric acid (H2SO4). The highest compressive strength obtain was 7.736 MPa. Bonding capacity between EAF slag and sand is increased by addition of sulphuric acid. Liquefaction effect and settlement was reduced compare to control sample. Photogrammetric approach seems to be a valuable way to calculate settlement of a structure. Soil stabilization with EAF slag waste material with some deeper studies can be a useful method to treat non-cohesive soils.