PSI- Issue 9

Costanzo Bellini et al. / Procedia Structural Integrity 9 (2018) 179–185 Bellini et al./ Structural Integrity Procedia 00 (2018) 000–000

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MPa) and to impact (4.5 Nm), that are compatible with stone application. Moreover, the Fibrelam ® has a remarkable stiffness, testified by a maximum deformation of 0.8 mm/m, which allows the sandwich structure to be used without any kind of support and a flames extinguish time of only 4 seconds after a 60-second exposure; its density is 2.5 Kg/m 2 . The stone tiles were in Perlato Royal of Coreno or in Absolute Black granite. Perlato Royal of Coreno is characterized by a high strength to wear and to impact that together to its resistance to weather agents carried out to be used for buildings. It has a density of 2650 Kg/m 3 ; it has a compressive strength of 166 MPa and a tensile strength of 10 MPa. The Absolute Black granite is very hard and since it is available in small volumes, it has a great commercial value. It has a density of 3030 Kg/m 3 ; it has a compressive strength of 295 MPa and a tensile strength of 27 MPa. The self-produced composite sandwich was glued to stone by means of an adhesive. Two adhesive were used: the Scotch-Weld TM EC-2216 B/A Gray of 3M TM and the Scotch-Weld TM AF163-2k of 3M TM . The commercial sandwich Hexcel Fibrelam ® was glued to stone only by means of the resin Scotch-Weld TM AF163 2k of 3M TM , since it allows to reach the best geometrical precision in gluing, so taking full advantage of the high precision of the commercial sandwich. For each test repetition, the obtained eighteen tiles (twelve stone with DIAB core and six with Fibrelam ® core) had a thickness of 10 mm or 12 mm that was reduced by removing the stone surface through a grader. After bonding to sandwich panels, each hybrid tile was cut with a diamond saw to produce samples measuring 40 mm x 200 mm for 3 point bend tests. All the samples manufactured are shown in Table 1. The obtained samples were submitted to the 3-point bend test, according with the UNI EN 12372 standard for stone products. In detail, the width of the sample should be between 25 mm and 100 mm and it has to be twice the size of the largest grain in the stone. The sample length should be six times its thickness, while the distance between the two pins that sustain the sample should be five times its thickness.

Table 1. Experimental plan Stone typology

Core type

Adhesive

Sample dimensions [mm] width x length x (thickness)

Replications

40x200x(6+12) * ; 40x200x(4+12) * ; 40x200x(3+12) * ; 40x200x(6+12) * ; 40x200x(4+12) * ; 40x200x(3+12) * ; 40x200x(6+10) * ; 40x200x(4+10) * ; 40x200x(3+10) * ; 40x200x(6+12) * ; 40x200x(4+12) * ; 40x200x(3+12) * ; 40x200x(6+12) * ; 40x200x(4+12) * ; 40x200x(3+12) * ; 40x200x(6+10) * ; 40x200x(4+10) * ; 40x200x(3+10) * ;

EC-2216

DIAB P60

Perlato Coreno marble

AF163-2k

Fibrelam ®

AF163-2k

5

EC-2216

DIAB P60

Absolute Black granite

AF163-2k

AF163-2k

Fibrelam ®

* 3-point-bend test. (X+Y): X=Stone, Y= sandwich structures.