Avaliação de misturas cimentícias para impressão 3D com desempenho térmico otimizado

Abstract

The development of 3D printed concrete mixes has been significantly studied during the last few years. However, the optimization of the thermal comfort of printed structures still requires further improvement. Therefore, the objective of the present study is to evaluate the effect of replacing natural sand by light expanded clay aggregate (LECA) on the properties of Portland-based 3DCP mixes. The mixtures were defined by a 2² factorial design with independent factors as the substitution content (% sub) of sand by LECA and the aggregate relation to binders ratio (a/b). The substitution of natural sand by LECA was carried out in volume% due to the difference in density, to maintain the granulometric distribution of the mixes. The compression flow technique together with the well-known consistency table were used to evaluate the rheological behavior of 3DCP mixes containing aggregates with up to 1.2 mm in maximum diameter. The experimental results show that the substitution of sand by LECA increased the yield stress of the mixes and improved their constructability, maintaining the same workability, compressive strength and porosity as the reference LECAfree mixture. The thermal insulation behavior of the mixes was improved by the use of LECA in the composition. The thermal behavior of the mixes was modeled and an equation dependent only on the (%sub) factor was found.