Diseño y elaboración de mezclas de hormigón con materiales reciclados

Abstract

This project focuses on the development of a sustainable concrete, replacing gravel with recycled concrete of different resistances, obtained from Holcim company, and replacing the cement with fly ash, obtained from the kilns used to make handmade bricks. The aggregates were characterized, and the optimum percentage of recycled concrete was determined by the test method for Bulk Density (“Unit Weight”), with the combination of all the aggregates that intervene in the mixture. To determine the optimum percentage of fly ash, compression, bending and tensile tests were carried out on mixtures made with different percentages. We worked with three types of ash: the material that passed the sieve Nº200, the material that passed the sieve Nº100 and with SikaFume. Finally, a mixture was made with the union of the two recycled materials. Both natural and recycled aggregates fulfilled the necessary characteristics for manufacturing of concrete. The optimum percentage of recycled concrete was 23%, whose compressive strength decreased by 2%. The ash that passes the sieve Nº200 was the one that presented better results, with an optimum percentage of 10%, the resistance to compression decreased by 3%. For concrete made with both recycled materials, tensile and flexural strengths decreased by 8% and 20%, respectively. The compression strength of the mixture reached 201 kg/cm2 after 14 days of curing. In addition, a reduction of 10% in energy used and CO2 emitted into the atmosphere, and a 9% reduction in cost was achieved with respect to the standard concrete.