Sustainable Concrete with Rice Husk Ash (RHA) for Marine Structures

Ingeniería Civil, Universidad Peruana de Ciencias Aplicadas, Lima, Perú

^a Corresponding author: u201417614@upc.edu.pe

Abstract

In recent years, attention has focused on addressing the environmental problems caused by the use of construction materials, proposing to develop new environmentally friendly concrete; One of the alternatives that has emerged is to replace cement or aggregates with agricultural waste because its treatment is expensive and not very sustainable; This is the case of rice husk ash (RHA), the main agricultural residue resulting from this cereal, which represents an abundant production worldwide. Marine reinforced concrete structures are in constant exposure to the marine environment, so that their structural capacity and useful life are affected by the breakdown of aggregates, which cause a greater amount of free CaO and MgO in concrete mixtures, and the penetration of chloride ions, which destroy the passive layer of steel and produce cracks in the concrete that cause loss of load and structural damage. In this investigation, cylindrical specimens of conventional concrete and sustainable concrete with cement replacement percentages of 5%, 10% and 15% RHA have been developed. The results show that for a 5% RHA replacement, the compressive strength is greater than conventional concrete at an early age; the disintegration of the aggregates decreases, being for the fine of 9.86% and for the coarse aggregate of 4.34%, the penetrability of sulfate ions decreases as the percentage of RHA replacement increases, the permeability of conventional concrete is much greater with respect to RHA replacement concrete and, finally, the unit cost analysis per cubic meter of RHA concrete is less than conventional concrete