https://hdl.handle.net/10259/6252 Thu, 23 Apr 2026 03:22:43 GMT 2026-04-23T03:22:43Z https://hdl.handle.net/10259/10124 Recycled polyamide mortars modified with non-ionic surfactant: physical and mechanical strength after durability tests Salas García, Miguel Ángel; Gadea Sainz, Jesús; Gutiérrez González, Sara; Horgnies, M.; Calderón Carpintero, Verónica This paper presents an investigation into the incorporation of polyamide powder waste in mortars with a polymeric organic soluble non-ionic surfactant. Several samples were prepared by replacing the aggregate with amounts of 0, 25, 50, 75 and 100 % polyamide powder, to obtain lightweight materials. It was found that the presence of powder waste modifies the characteristics of fresh and hardened mortar while maintaining suitable properties such as workable life, water retention, vapour permeability and bonding in mixtures with up to 50 % of sand replaced by polyamide. The surfactant modifies the matrix microstructure and contributes to the hydration of the various cement phases. The assessed mechanical strength after performing the accelerating ageing tests remains sufficient with moderate amounts of waste, meaning that these mortars possess good overall durability. The experimental results showed that the addition of polyamide waste makes it possible to obtain lightweight materials more environmentally sustainable for use as masonry mortars. Fri, 01 Jan 2016 00:00:00 GMT https://hdl.handle.net/10259/10124 2016-01-01T00:00:00Z https://hdl.handle.net/10259/10114 Developing an adaptive virtual learning environment for sustainable learning in individuals with Down syndrome Arranz Barcenilla, Cristina; Pavía, Sara; Sáiz Manzanares, María Consuelo; Alameda Cuenca-Romero, Lourdes; Gutiérrez González, Sara This study focuses on the design and technological development of a virtual learning environment tailored to instruct students with Down Syndrome in sustainability concepts. The system grants students access to free software designed for teaching fundamental principles related to environmental awareness, recycling, and sustainable construction. The platform's creation is underpinned by Fogg's Persuasive Technology methodology, emphasizing the acquisition of new competencies through technology to promote sustained engagement with novel technology habits, thereby facilitating a seamless integration into the learning process. The study utilized a phased approach: content adaptation, technological development, and usability evaluation. It emphasized collaboration with stakeholders, including Down Syndrome associations and academic institutions. Recommendations include adherence to universal design principles and further research on the platform's impact. The platform's usability was assessed in terms of simplicity, intuitiveness, performance, robustness, and accessibility. Observations revealed that an impressive 91.7% of students derived genuine enjoyment from the learning tool. Feedback from both tutors and professionals indicated that 91.4% found the virtual learning environment to be well-organized, 88.6% regarded the content as suitable and comprehensible, and nearly 80% affirmed its utility for their professional practice. Mon, 01 Jan 2024 00:00:00 GMT https://hdl.handle.net/10259/10114 2024-01-01T00:00:00Z https://hdl.handle.net/10259/10107 Electro-welded lattice reinforcement in reinforced concrete ribbed slabs Aragón Torre, Ángel; Pérez Acebo, Heriberto; Aragón Torre, Guillermo; Salas García, Miguel Ángel Shear strength of precast concrete ribbed slabs reinforced with electro-welded lattice girders of variable height is experimentally verified. Technical justification is given for the use of high latticework in the reinforcement of precast lightweight double-tee ribbed slabs and precast reinforced concrete slabs 30 cm in thickness. It was established that the contribution of concrete to shear strength was always higher than the expected values according to Spanish standards. Furthermore, as low lattice ribbed slabs exhibited lower ultimate shear strength values than the ones expected based on the standards, the need arose to provide an adequate height of lattices in ribbed slabs to ensure anchorage of the compressed area in order to develop the strut-and-tie mechanisms. Consequently, lattice girders with approximately 80% of specimen height are highly recommended in reinforced concrete ribbed slabs, when the length of lattice chords is 20 cm. Fri, 01 Jan 2021 00:00:00 GMT https://hdl.handle.net/10259/10107 2021-01-01T00:00:00Z https://hdl.handle.net/10259/10106 Introduction of recycled polyurethane foam in mastic asphalt Salas García, Miguel Ángel; Pérez Acebo, Heriberto The aim of this paper is to analyse the suitability of recycled polyurethane (PU) foam as a binder modifier in mastic asphalts (MA). The results show that harder bitumen is achieved with an increasing percentage of PU, up to 5 %, when the workability of the sample becomes poor. A MA mix with a 4 % of PU in bitumen was manufactured. A lower indentation was observed when compared to a virgin sample, and it was established that the modified MA can be used on heavy-traffic roads. These results suggest a promising use of this waste polymer. Mon, 01 Jan 2018 00:00:00 GMT https://hdl.handle.net/10259/10106 2018-01-01T00:00:00Z