Simultaneous Initiation of Nitromethane in Two Holes by Pulsed Wire Discharge for Crack Control of a Concrete Block

2019 ◽  
Vol 6 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Shigeru Tanaka ◽  
Masatoshi Nishi ◽  
Makoto Yamaguchi ◽  
Ivan Bataev ◽  
Kazuyuki Hokamoto
1906 ◽  
Vol 61 (1578supp) ◽  
pp. 25282-25283
Author(s):  
O. U. Miracle

PCI Journal ◽  
1988 ◽  
Vol 33 (4) ◽  
pp. 124-145 ◽  
Author(s):  
Fritz Leonhardt

Author(s):  
Are Håvard Høien ◽  
Charlie C. Li ◽  
Ning Zhang

AbstractRock bolts are one of the main measures used to reinforce unstable blocks in a rock mass. The embedment length of fully grouted bolts in the stable and competent rock stratum behind the unstable rock blocks is an important parameter in determining overall bolt length. It is required that the bolt section in the stable stratum must be longer than the critical embedment length to ensure the bolt will not slip when loaded. Several series of pull tests were carried out on fully grouted rebar bolts to evaluate the pull-out mechanics of the bolts. Bolt specimens with different embedment lengths and water/cement ratios were installed in either a concrete block of one cubic meter or in steel cylinders. Load displacement was recorded during testing. For some of the bolts loaded beyond the yield load, permanent plastic steel deformation was also recorded. Based on the test results, three types of failure mechanisms were identified, corresponding to three loading conditions: (1) pull-out below the yield strength of the bolt steel; (2) pull-out between the yield and ultimate loads, that is, during strain hardening of the steel; and (3) steel failure at the ultimate load. For failure mechanisms 2 and 3, it was found that the critical embedment length of the bolt included three components: an elastic deformation length, a plastic deformation length and a completely debonded length due to the formation of a failure cone at the borehole collar.


1996 ◽  
Vol 40 ◽  
pp. 1009-1014
Author(s):  
Kazutoshi KAN ◽  
Tuyoshi HORIGUCHI ◽  
Hideaki TARE

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4174
Author(s):  
André M. Santos ◽  
Ângelo J. Costa e Silva ◽  
João M. F. Mota ◽  
João M. P. Q. Delgado ◽  
Fernando A. N. Silva ◽  
...  

The understanding of the mechanical fixation behavior of coatings is crucial for a better comprehension of the bonding systems, especially at the interface between the mortar and the substrate. Physical adherence is related, among other things, to the contents of the materials used in the roughcast and mortar coatings, due to the colloidal water penetration into the pores of the substrate. This work evaluated the influence of different lime solution additions replacing the kneading water in the preparation of roughcast and mortar coatings. Two types of substrates were investigated:ceramic bricks and concrete blocks. Three wall masonry panels were constructed, with dimensions of 220 × 180 cm2, one of concrete block and two of ceramic bricks, followed by the application of roughcast and mortar coating with an average thickness of 5 mm and 20 mm, respectively. Direct tensile bond strength tests were performed and the results, with a 95% confidence level, showed that substrate ceramic and treatment in the roughcast exhibited a better behavior regarding the distribution of the tensile bond strength of the tested specimens. However, no significant differences of the amount of addition used (0%, 5%, 10% and 15%) on the tensile bond strength were observed.


2021 ◽  
Vol 141 ◽  
pp. 107129
Author(s):  
Kang Qi ◽  
Yong Yang ◽  
Rui Sun ◽  
Guofang Hu ◽  
Xin Lu ◽  
...  

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