Pervious concrete, plastic concrete and controlled low strength material- a special applications concrete

Abstract

The paper presents the study carried out for three special concretes like Pervious Concrete, Plastic Concrete and Controlled Low Strength Materials (CLSM) using locally available materials. Pervious concrete is a concrete with high porosity. It is used in a wide range of applications including pervious pavements and helps in improving pavement skid resistance and reducing hydroplaning. This concrete was designed to meet the requirement of 28-day compressive strength of 10 MPa and water permeability of 0.50 cm/sec. Plastic concrete has low compressive strength but higher ductility and lower permeability. It is used for creating an impermeable barrier (cut-off wall) for containment of contaminated sites or seepage control in highly permeable dam foundations. This concrete was designed to meet the requirement of 28-day unconfined compressive strength of 1.5 to 2.5 MPa and confined compressive strength of 2.5 to 3.5 Mpa at confining pressure of 4 Kg/cm2. Controlled Low Strength Material (CLSM) or flowable fill mixtures are typically specified and used in place of compacted fill especially for backfill, utility bedding, void fill and bridge approaches. CLSM is a self-compacting, flowable, low strength cementitious material which suits the requirement of different applications such as excavatable backfill and structural backfill. The properties of CLSM that were investigated included bleeding, density of hardened CLSM, permeability and unconfined compressive strength at 7 days and 28 days age.