Parametric study on permeability of concrete made of brick chips

Abstract

Permeability characteristic of concrete made from brick aggregate concrete is evaluated and compared with concrete made from stone aggregate. For this, four different classes of brick according to Bangladesh standard are selected. Several tests are conducted on whole new brick as well as aggregate prepared from them before concrete samples were prepared. These tests include crushing strength, absorption, LA abrasion and density. Using brick aggregate prepared from these four different classes of bricks, concrete samples are prepared using ACI mix design methods. Strength of concrete that could be achieved using brick aggregate varied between 14 to 28 MPa. Simultaneously, concrete samples were prepared from stone aggregate as well. Like brick, representative tests are conducted on stone aggregate. Strength of concrete achieved using stone aggregate concrete varied between 24 to 46 MPa. These samples were then tested for permeability using the AT 315 machine which applies water at a certain pressure on concrete samples for a specified period of time. Water pressure and duration of its application were fixed as per EN 12390‐8: “Depth of Penetration of Water under Pressure”. Results of permeability test indicate that permeability of concrete made from brick aggregate is far greater than that of concrete made from stone aggregate of identical strength. This increase in permeability depends on classes of bricks used. For example, concrete prepared from S class brick is about 200% more permeable than concrete of identical strength but made from stone aggregate. Further, it was found that permeability of concrete made from brick aggregate is directly influenced by crushing strength of brick, absorption and LA abrasion value of brick aggregate. All of these parameters showed linear variation with permeability of concrete prepared from them.