Development of Geopolymers as Substitutes for Traditional Ceramics for Bricks with Chamotte and Biomass Bottom Ash.

The greater environmental awareness, new environmental regulations and the optimization of resources make possible the development of sustainable materials as substitutes for the traditional materials used in construction. In this work, geopolymers were developed as substitutes to traditional ceramics for brick manufacture, using as raw materials: chamotte, as a source of aluminosilicate, and biomass bottom ashes from the combustion of almond shell and alpeorujo (by-product produced in the extraction of olive oil composed of solid parts of the olive and vegetable fats), as the alkaline activator. For the feasibility study, samples were made of all possible combinations of both residues from 100% chamotte to 100% biomass bottom ash. The tests carried out on these sample families were the usual physical tests for ceramic materials, notably the compression strength test, as well as colorimetric tests. The freezing test was also carried out to study the in-service behavior of the different sample groups. The families with acceptable results were subjected to Fourier transform infrared (FTIR) analysis. The results of the previous tests showed that the geopolymer was indeed created for the final families and that acceptable mechanical and aging properties were obtained according to European standards. Therefore, the possibility of creating geopolymers with chamotte and biomass bottom ashes as substitutes for conventional ceramics was confirmed, developing an economical, sustainable material, without major changes in equipment and of similar quality to those traditionally used for bricks.

Study of the Incorporation of Ladle Furnace Slag in the Manufacture of Cold In-Place Recycling with Bitumen Emulsion.

Cold in-place recycling with bitumen emulsion is a good environmental option for road conservation. The technique produces lower CO2 emissions because the product is manufactured and spread in the same location as the previous infrastructure, and its mixing with bitumen emulsion occurs at room temperature. Adding materials with cementitious characteristics gives the final mixture greater resistance and durability, and incorporating an industrial by-product such as ladle furnace slag (of which cementitious characteristics have been corroborated by various authors) enables the creation of sustainable, resistant pavement. This paper describes the incorporation of ladle furnace slag in reclaimed asphalt pavements (RAP) to execute in-place asphalt pavement recycling with bitumen emulsion. Various test groups of samples with increasing percentages of emulsion were created to study both the density of the mixtures obtained, and their dry and post-immersion compressive strength. To determine these characteristics, the physical and chemical properties of the ladle furnace slag and the reclaimed asphalt pavements were analyzed, as well as compatibility with the bitumen emulsion. The aforementioned tests define an optimal combination of RAP (90%), ladle furnace slag (10%), water (2.6%), and emulsion (3.3%), which demonstrated maximum values for compressive strength of the dry and post-immersion bituminous mixture. These tests therefore demonstrate the suitability of ladle furnace slag for cold in-place recycling with bitumen emulsion.

Surface Treatments with Dichloromethane to Eliminate Printing Lines on Polycarbonate Components Printed by Fused Deposition Modelling Technology.

Additive manufacturing, framed within the Industry 4.0. concept, is one of the processes that has witnessed greater development in the last years. Within this subject fused deposition modelling (FDM) printing technology is mainly dedicated to polymers and capable of providing components or elements of sufficient quality for different sectors. However, due to the process there can be a series of surface irregularities, which although they do not affect the required dimensional tolerances, they can cause problems in the useful life of the printed object in its interactions with the environment, as well as poor aesthetic qualities. Based on the above, this paper presents a series of chemical surface treatments capable of providing a surface that avoids undesired printing lines. For this purpose, fast, economical and environmentally sustainable treatments are used that obviously do not deteriorate the structure of the component or degrade the material surface. A complete study is therefore presented in which the different variables of the process are evaluated, as well as those of the printing technology, such as the layer height, coating, infill density, etc. The development of this project achieves a field of application of the detailed chemical treatment to obtain smooth surfaces, without degradation of the final part and with the appropriate dimensional tolerances.

Study of the Incorporation of Biomass Bottom Ashes in Ceramic Materials for the Manufacture of Bricks and Evaluation of Their Leachates.

Scarcity of raw materials, reduction of greenhouse gas emissions and reduction of waste disposal in landfills are leading to the development of more sustainable building materials. Based on these lines, this work studies the incorporation of biomass bottom ashes into ceramic materials for brick manufacture, in order to reuse this currently unused waste and reduce clay extraction operations. To this end, different groups of samples were made with different combinations of clay and biomass bottom ashes, from 100% clay to 100% biomass bottom ashes. These samples were shaped, sintered and subjected to the usual physical tests in ceramics. In turn, the mechanical resistance, color and leaching of the contaminating elements present were studied. The physical and mechanical tests showed that the results of all the families were adequate, achieving compressive strengths of over 20 MPa and leaching of the contaminating elements acceptable by the regulations. Therefore, a sustainable range of ceramics was developed, with specific properties (porosity, density, resistance and color), with a waste that is currently unused and sustainable with the environment.