Novos compósitos para materiais de construção civil contendo sedimentos de dragagem de porto marítimo, cinza de madeira de bracatinga e cal residual

Abstract

With the growth of industrial and municipal wastes generation and overcrowding of their landfills, it increases the necessity to develop alternatives for their economically and ecologically efficient disposal. This research presents results of three type of industrial wastes utilization - dredged sediment (DS) from the Seaport of Paranaguá, wood ashes (WAB) of bracatinga (Mimosa scabrella) and lime production wastes (LPW) - as raw materials for production of construction materials. DS was used as aggregate (30 -70 wt.%), WA – as filler (5 to 40%) and LPW (15 - 30%) - as a binder. The raw materials and final products were characterized and testes by the following complementary methods: XRF, XRD, SEM with EDS, uniaxial compressive strength, water absorption, water resistance, linear expansion and bulk density. It was determined that the uniaxial compressive strength increases with increasing content of the LPW and of the curing time. The max resistance of the test samples (TSs) reaches at the 3rd day of 2.39 MPa, at the 28th day of 2.44 MPa, at the 60th of 4.51 MPa, at the 90th day of 5.45 MPa, and 180th day of 8.77 MPa. The water absorption on the 28th day of curing ranged from 9.50% to 17.20% and on the 90th day was decreased, ranging from 8.30% to 16.60%. All these changes of TSs’ mechanical properties took place due to chemical interaction of the initial components in the moist alkaline outdoors condition with partial chemical destruction of DS and WA particles and with synthesis of new crystalline and amorphous minerals, mainly of carbonates and CSH compositions. New materials can be economically attractive due to cheap industrial wastes utilization as raw materials for manufacturing of civil construction materials and, thus, considerable reduction of their price. Widespread use of this ecologically clean method of wastes utilization could significantly improve the environmental situation of ocean coastal and industrial regions and decrease consuming of natural resources for civil construction.