Influência da umidade no comportamento estrutural de alvenaria de tijolos de solo-cimento com diferentes tipos de juntas finas

Abstract

Moisture plays a determining role in the mechanical performance of soil-cement masonry. In this research, the mechanical behavior of soil-cement brick masonry with thin joints was analyzed as a function of air relative humidity (RH). Two types of soil-cement bricks (TSC1 and TSC2) and three types of thin joints were used: acrylic adhesive, tile adhesive mortar, and polymer composite. The bricks and the joint materials were physically, chemically, and mechanically characterized. Prisms, small walls, and walls were constructed to determine compressive and shear strength under different RH conditions and under saturation. The results indicated that the critical state occurs under material saturation and that RH significantly influences mechanical performance. In the prisms, joints made with tile adhesive mortar exhibited the highest compressive strengths at all RH levels. A reduction in compressive strength from dry to saturated conditions ranging from 57% to 59% was observed for all joint types, indicating that saturation is decisive in strength reduction. In all cases, a loss of stiffness was observed with increasing RH, with the lowest deformation moduli occurring under saturated conditions, confirming the significant influence of moisture on masonry deformability. The failure mode of the prisms was influenced by the joint type used. Saturated small walls exhibited a reduction of approximately 48.87% in compressive strength and about 17% in deformation modulus. The walls showed similar behavior, with reductions of 55.10% in compressive strength and 22.33% in deformation modulus, respectively, when transitioning from dry to saturated conditions. It is concluded that the mechanical behavior of soil-cement brick masonry is directly related to air relative humidity, making it essential to consider this variable in load-bearing capacity calculations for structural design, in order to ensure the safety, durability, and reliability of masonry.