Use of Solid Waste (Foundry Slag) Mortar and Bamboo Reinforcement in Seismic Analysis for Single Storey Masonry Building

摘要

The conversion of large amount of solid waste (foundry slag) into alternate source of building material will contribute not only as a solution to growing waste problem, but also it will conserve the natural resources of other building material and thereby reduce the cost of construction. The present work makes an effort to safe and economic use of recycle mortar (1:6) as a supplementary material. Conventional and recycled twelve prisms were casted with varying percentage of solid waste (foundry slag) added (0, 10, 20, 30 %) replacing cement by weight and tested under compression testing machine. As the replacement is increasing, the strength is decreasing. 10 % replacement curve is very closed to 0 % whereas 20 % is farther and 30 % is farthest. 20 % replacement was chosen for dynamic testing as its strength is within permissible limit as per IS code. A 1:4 scale single storey brick model with half size brick was fabricated on shake table in the lab for dynamic testing using pure friction isolation system (coarse sand as friction material μ = 0.34). Pure friction isolation technique can be adopted economically in developing countries where low-rise building prevails due to their low cost. The superstructure was separated from the foundation at plinth level, so as to permit sliding of superstructure during severe earthquake. The observed values of acceleration and displacement responses compare fairly with the analytical values of the analytical model. It also concluded that 20 % replacement of cement by solid waste (foundry slag) could be safely adopted without endangering the safety of the masonry structures under seismic load.To have an idea that how much energy is dissipated through this isolation, the same model with fixed base was tested and results were compared with the isolated free sliding model and it has been observed that more than 60 % energy is dissipated through this pure friction isolation technique. In case of base isolation, no visible cracks were observed up to the table force of 4.25 kN (1,300 rpm), whereas for fixed base failure started at 800 rpm.To strengthen the fixed base model, bamboo reinforcement were used for economical point of view. Another model of same dimension with same mortar ratio was fabricated on the shake table with bamboo reinforcement as plinth band and lintel band. In addition another four round bamboo bars of 3 mm diameter were placed at each of the four corners of the model. The building model was tested and found very encouraging and surprising results. The model failure started at 1,600 rpm, which means that this model is surviving the double force in comparison with the non-bamboo reinforcement.