Pilot Scale Production of Precast Concrete Elements with Wood Biomass Ash

Optimal Design of Sustainable Reinforced Concrete Precast Hinged Frames

Sustainable development requires improvements in the use of natural resources. The main objective of the present study was to optimize the use of materials in the construction of reinforced concrete precast hinged frames. Proprietary software was developed in the Python programming language. This allowed the structure's calculation, verification and optimization through the application of metaheuristic techniques. The final cost is a direct representation of the use of materials. Thus, three algorithms were applied to solve the economic optimization of the frame. By applying simulated annealing, threshold accepting and old bachelor's acceptance algorithms, sustainable, non-traditional designs were achieved. These make optimal use of natural resources while maintaining a highly restricted final cost. In order to evaluate the environmental impact improvement, the carbon-dioxide-associated emissions were studied and compared with a reference cast-in-place reinforced concrete frame. The results showed designs with reduced upper slab and lateral wall depth and dense passive reinforcement. These were able to reduce up to 24% of the final cost of the structure as well as over 30% of the associated emissions.

Modeling and Experimental Verification of the Performance of Polymer Composite Reinforcing Bars of Different Types in Concrete of Different Density

Currently, there is a scientific and practical deficit in new methods of integrated technological and design solutions based on improving the properties of concrete as the primary material that perceives compressive loads, and its joint work with various types of reinforcing rods. A new system using an integrated engineering approach to the design of building structures is proposed, which involves minimizing their cost and weight through numerical simulations and an experimental verification of the operation of reinforcing bars made of various materials in concrete of various densities. The control of the bearing capacity of reinforced building structures on the example of compressed elements is proposed to be carried out using the developed recipe-technological methods at the manufacturing stage. The economic and environmental efficiency of nano modification with the help of production waste and the use of lightweight dispersion-reinforced concrete to obtain such structures was revealed. The most effective concrete formulations showed strength gains ranging from 10% to 34%. Ultimately, this led to an increase in the bearing capacity of the elements up to 30%. The application of such an integrated lean approach will allow saving up to 20% of resources during construction.

Construction Solutions and Materials to Optimize the Energy Performances of EPS-RC Precast Bearing Walls

The design and employment of envelope components showing high thermal performances for new buildings and deep renovations must take into account the overall impact of the production process in terms of environmental sustainability. To this end, precast construction solutions and secondary raw materials provide added value to the energy quality of building products. With regard to the abovementioned issues, the paper is focused on the performance optimization of expanded polystyrene-reinforced concrete (EPS-RC) precast bearing walls, already developed and patented within a previous research project entitled “HPWalls. High Performance Wall Systems”, and herein improved according to two complementary requirements: on the one hand, the addition of recycled EPS particles to the concrete mixtures and, thus, the assessment by lab tests of the correlation between the thermal and mechanical properties for several mix-design specimens; on the other hand, a study using analytical simulations of the most suitable joint solutions among modular panels in order to prevent thermal bridges. The achieved results validate the proposed optimization strategies and provide reliable data for market applications in the building sector.

Influence of Wood Fly Ash on Concrete Properties through Filling Effect Mechanism

This paper presents the results of an experimental study aimed at determining the influence of wood fly ash (WFA) from three Croatian power plants on the properties of concrete. First, the chemical and physical properties of WFA’s were determined. It was found that these properties are highly influenced by combustion technology, the type and parts of wood used as fuel, and the local operating conditions. Subsequently, workability, heat of hydration, stiffness development, 28-day compressive strength, apparent porosity, and capillary absorption were determined on concrete mixes prepared with WFA as cement replacement from 5–45% by weight. Cement replacement up to 15% with the finest WFA accelerated hydration, stiffness development, and increased compressive strength of concrete up to 18%, while replacement with coarser WFA’s led to a decrease in compressive strength of up to 5% and had more gradual heat liberation. The dominant effect that could explain these findings is attributed to the filler and filling effect mechanisms. At the same time replacement content of up to 45% had very little effect on capillary absorption and could give concrete with sufficiently high compressive strength to be suitable for construction purposes.