Coniferous Trees as Bioinspiration for Designing Long Reinforced Prestressed Concrete Columns.

This article contains the results of identifying the potential of coniferous trees to act as bioinspiration for the structural design of columns in single-story warehouses subjected to high wind velocity and severe seismic action. This study starts by analyzing the biomechanics of coniferous trees, continues with an abstraction of the relevant features, and ends with the transfer of a design methodology for long reinforced and prestressed concrete columns. To verify the applicability and validity of the mathematical relationships extracted from the bibliographic study to characterize the biomechanics of coniferous trees, a study site is conducted for Norway spruce trees felled by the wind in the Bilbor area. The design methodology for long reinforced and prestressed concrete columns bioinspired by the Norway spruce trees is experimentally validated using two case studies. The first case study deals with the effect of centric prestressing on long concrete columns, and the second on the influence of the walnut shell powder on the adhesion of the reinforcement in concrete. The case studies presented aim to transfer some characteristics from trees to reinforced concrete to improve the performance of long columns under horizontal forces. The results obtained indicate a good approximation of the trees' structural behavior for this site and for ones investigated by other researchers in different forests.

Assessment of Limestone Waste Addition for Fired Clay Bricks.

Our aim was to investigate the feasibility of using limestone waste resulting from stone processing for the manufacturing of fired clay bricks. Waste materials were considered as a partial replacement for clays to reduce the exploitation of natural resources and as a response to the climate neutrality commitments. The samples were prepared to have a waste content of up to 15% and were fired at a temperature of 900 °C. The chemical and mineralogical composition and the physical analysis of raw materials were investigated by using SEM-EDS and XRD diffraction. The result showed an increase in CaO in the clay mixture due to the presence of limestone, which reduced the shrinkage of the products' compressive strength, up to 55% for samples with a higher content of limestone (15 wt.%), and influenced the samples' color by making them lighter than the reference sample.

Volcanic Tuff as Secondary Raw Material in the Production of Clay Bricks.

The present work examines an innovative manufacturing technique for fired clay bricks, using tuff as a secondary raw material. Samples were made of clay and tuff (0-30 wt.%) fired at 900 to 1100 °C. The chemical and mineralogical compositions and physical and thermal analyses of raw materials were investigated by using SEM-EDS, RX and DTA-TG curves. The samples were analysed from the mineralogical, technological and mechanical points of view. The result show that the tuff's presence in the clay mixtures considerably reduced the shrinkage of the product during the firing process, and the manufactured samples were of excellent quality. The compressive strength of the bricks varied from 5-35.3MPa, being influenced by the tuff content, clay matrix properties and firing temperatures. Finally, the heat demand for increasing the temperature from room to the firing temperature of the sample with 10% tuff content was 22%.