*3.4. Three-Point Bend Strength*

Table 3 presents the three-point bend strength values of ENS-15 and pure epoxy resin.

**Table 3.** Three-point bend strength of ENS-15 and epoxy resin.


Figure 3 shows the stress vs. strain curves obtained by the three-point bending test of ENS-15 developed and of the pure epoxy resin. Mechanical strength, or the stress at which the material breaks, is the most important property for structural materials.

The mechanical bending resistance of ENS-15 was 33.5 ± 4.0 MPa, with a strain ranging from 0.0 to 0.3.

When comparing the ENS bending strength results of those found by Carvalho et al. [15] for Stellar™ (36.61 ± 2.48 MPa) with those also found by Carvalho et al. [6], artificial stone developed with quarry waste and 15% epoxy resin (32 ± 2 MPa), and by Gomes et al. [16], AOS artificial stone developed with brick waste and quarry dust with 20% epoxy resin (30 ± 3 MPa), it is noticeable that the values for ENS-15 are in accordance with those found by other authors for similar materials.

According to Chiodi Filho and Rodriguez [30], ornamental stones used as coatings in civil construction, with bending strength above 20 MPa, are classified as highly resistant materials. As ENS-15 presented flexural strength above this value, it can be classified as a high-strength engineered stone, enabling it to be used on tops and countertops without restriction, as well as in internal and external walls.

The GSO ASTM C503/2015 [32] standard specifies that calcitic marble bend strength must be greater than 7 MPa. The bend strength values found by the ENS developed in this work represent about five times this value. Therefore, it is possible to affirm that the material developed represents a formidable alternative to replace calcitic marble, which could result in material savings, since the greater resistance would make it possible to produce the same materials with smaller dimensions.

**Figure 3.** Mechanical behavior of ENS-15 and the pure epoxy resin in 3-point bend strength tests.
