Adhesive durability and joint reliability, strictly related to the bonding agents, are key parameters still under evaluation in civil as well as in other engineering fields. Moisture, different environmental agents and temperature (in particular) can strongly affect the performance of the adhesive joints over the time limiting their applicability. The environmental temperature may exceed the glass transition temperature (T_g) of the adhesive formulation entailing relevant changes in its properties, determining, for instance, a transition from a hard to a rubbery behaviour, thus compromising its specific application. Furthermore, due to changes of the temperature values, the structural adhesive can be naturally subjected to a delay or increase in the curing degree. Hence adverse or positive changes in strength and stiffness can be manifested. Within this framework, the topic of the present paper is the study of the hygro-thermal durability of two commercial epoxy resins, suitable for civil engineering applications, respect to the immersion in tap water and sea water for a period of fifteen months at the temperature of 30 °C. To this scope a wide experimental program was developed comprising both End Notch Failure (ENF) tests on the adhesive samples (adherent in glass fiber reinforced polymer, GFRP) for evaluating the pure fracture energy in Mode II of the resins and the water absorption tests for resins and GFRP materials. In general, the results, in terms of fracture energy, show an initial increment (first three-four months) followed by a decrement up to the reaching of a plateau (in the ninth-twelfth month of conditioning). For what concerns the water absorption, the results show that the equilibrium value of both resins is reached in about one month, while that of GFRP samples depend on the type of liquid: three months for tap water and about five months for sea water. Considering the lower activity of the seawater, the longer time to reach the equilibrium value was an expected result.

与粘接剂严格相关的胶粘剂耐久性和接头可靠性是民用以及其他工程领域仍在评估的关键参数。随着时间的流逝，水分，不同的环境因素和温度（尤其是温度）会严重影响粘合接头的性能，从而限制其适用性。环境温度可能超过粘合剂制剂的玻璃化转变温度（T _g ），从而导致其性能发生相关变化，例如确定了从硬到橡胶的转变，从而损害了其特定的应用。此外，由于温度值的变化，结构粘合剂可以自然地延迟或增加固化程度。因此，可以表现出强度和刚度的不利或积极变化。在此框架内，本文的主题是研究两种民用环氧树脂的湿热耐久性，适用于土木工程应用，相对于在该温度下在自来水和海水中浸泡15个月的时间而言30°C。在此范围内，开发了一个广泛的实验程序，包括对粘合剂样品（玻璃纤维增强聚合物中的粘合剂）进行的切口缺口失效（ENF）测试（GFRP），以评估树脂在模式II下的纯断裂能，以及树脂和GFRP材料的吸水率测试。总的来说，就断裂能量而言，结果显示出初始增加（前三至四个月），然后逐渐减小直至达到稳定水平（在调节的第九至十二个月）。关于吸水率，结果表明两种树脂的平衡值均在约一个月内达到，而GFRP样品的平衡值取决于液体类型：自来水为三个月，海水为约五个月。考虑到海水的活性较低，达到平衡值的时间较长是预期的结果。