Experimental Study of Impact Resistance of Ceramics and Composites

Analytical model to predict the lifetime of concrete members externally reinforced with FRP

“…The literature [2,3,5,13,[21][22][23]26,28,43,47,49] also reveals that v c and N depend on humidity and temperature as well, but these dependences are not strong. Ultimately, for concrete members with a carbonation depth greater than the cover, K IIC is close to 1.0 MPa m 0.5 [31,36,[44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], v c to 0.0015 m/s [22][23][24]31,36,41,[43][44][45][46], and N to 16 [18,24,41,43,59]. It is to note that N is the exponent and thus it is important to provide the model with a reliable value; however, N = 16 is simultaneously an accurate and preservative assumption.…”

“…the K II /K IIC ratio that dictates the upper bound is quite close to one. The crack velocity of this second regime is described by a relationship whose form is da/dt / exp(bÁK II /K IIC ), where b depends only on the material and environment [29,31,34,36,[42][43][44][45][46]49,50].…”

“…In order to plug into the model the actual values that K IIC , v c , and N assume in a specific concrete, instead of a priori values, tests have to be accomplished, either on-site or in laboratory [18,[22][23][24]29,31,36,39,41,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]. On the contrary to K IIC , however, v c and N are not simple to be measured; thus, it is more convenient to use the aforementioned values borrowed from literature.…”