Durability of PS-Polyurethane Dedicated for Composite Strengthening Applications in Masonry and Concrete Structures

Abstract

Polyurethane flexible joints (PUFJ) and fiber reinforced polyurethanes (FRPU) have shown great potential in the repair and protection of masonry and concrete structures. However, some questions have been raised about the durability of such solutions. The accelerated weathering and thermal stability tests carried out so far have shown the mechanical stability of PS-polyurethane in temperatures up to 100 °C and some UV-induced surface degradation. The paper reports the results from tensile tests of PS-polyurethane, used in the technologies mentioned above after being subjected to aging in different corrosive factors, a thermal analysis of unaged polymer which consists of DSC-TGA and dilatometry studies, and SEM-microscopy observation of the specimens with the indication of the elemental composition (EDS). PS-polyurethane showed low sensitivity to weathering with exposition to UV-radiation, some reactiveness to aqueous environments of a different chemical nature, and resistivity to soil and freezing in both air and water. SEM observations indicated changes in the composition of mineral fillers as the main effect of immersion in different water solutions. DSC-TGA studies showed the thermal stability of PS-polyurethane up to 200 °C and degradation proceeding in five stages. Dilatometry studies revealed that the first-degree thermal degradation over 200 °C causes a serious loss of mechanical properties.

Highly Dissipative Materials for Damage Protection against Earthquake-Induced Structural Pounding

“…Polyurethanes are well described in already mentioned works, e.g., [20,[22][23][24]. With respect to the proposed application in civil engineering, it is worth adding that materials from the family of polyurethanes are resistant to repeated hydration and repeated freezethaw cycles, as is shown in, e.g., [33], which describes the results of practical research conducted for airport aprons, or in paper [34], which presents the results of testing a polyurethane family member in the presence of water.…”

Phosphorus Release and Adsorption Properties of Polyurethane–Biochar Crosslinked Material as a Filter Additive in Bioretention Systems

“…On the one hand, the water retention capacity of polyurethane improved under multi-field coupling, due to the broken molecular chain and higher connectivity of the pore structure [20]. When subjected to soil, water and air, the structure of polyurethane showed no significant changes, indicating the good durability of its mechanical properties in the long term [21]. On the other hand, it has been widely recognized that polyurethane foams can be employed as highly efficient adsorbents in removing heavy metals [22], ammonium [23], nitrate [24] and some organic pollutants (e.g., dialkyl phthalates [25], oils and trichloromethane [26], etc.).…”

Modelling of Flexible Adhesives in Simple Mechanical States with the Use of the Darijani–Naghdabadi Strain Tensors and Kirchhoff–de Saint-Venant Elastic Potential

“…These structural connectors can be used as repair, strengthening or protection solutions in RC (reinforced concrete) and masonry structures, because they are capable of transferring high loads and large deformations [ 8 ]. They are constructed from special polyurethanes of non-linear and visco-elastic characteristic; thus, different material properties can be expected in cases of various strain rates [ 9 ] and various environmental conditions [ 10 ]. Model descriptions of PUFJ and FRPU are needed for calculations when practical engineering applications in buildings are considered.…”