Concrete fragmentation

Uses. Minols have historically been used in four types of ordnance, a) underwater (mines, torpedoes and depth charges) where the confinement of water offsets some of the loss of detonation velocity, b) blockbuster bombs in which a sustained and powerful impulse is more destructive than a high peak press, c) concrete fragmentation bombs where the high impulse will impart a satisfactory fragment velocity but will not pulverize the concrete they contact on impact, and d) in general purpose (GP) bombs... 

Breeching is a local perforation of the concrete element by the extremely high blast pressures of a close explosion. High velocity concrete fragments can result. Breeching failures are controlled by providing adequate reinforcement, concrete thickness and standoff distance to the explosive. 

A series of experiments were- conducted at the Illinois Institute of Technology Research Institute (IITRI) Test Facility to determine explosive sensitivity to impact by concrete fragments. Fig 15 simulates a situation where wall fragments resulting from donor detonation impact the acceptor. 

The concrete fragments utilized in this program were launched from a 12" gun as shown in Fig l6. This air gun is capable of launching fragments at a wide range of weights and velocities. 

In order to quantify microscopic damage, distribution of pore radii was also measured by the mercury intrusion method from concrete fragments at the three sites. After determining the pore distribution, the volume of pore radii over 0.5 pm was determined. This is because microvoids over 0.5 pm are dominantly responsible for deterioration of concrete. 

Scabbing Debris or fragments generated from the back face of an impacted object (typically a concrete or masonry wall). 

Figure B.6 Fragment impact phenomena for concrete structures.

Design for Spalling. Breeching, and Fragment Penetration. Test results have been used to empirically derive relationships for the reinforced concrete thickness required to prevent spalling, breeching, or fragment penetration. 

Design Criteria for Fragment Penetration. Complete penetration of concrete (perforation) by steel fragments can be prevented by using the minimum concrete thickness, t. (in) given by the following relationship ... 

In 1981, Science magazine again asked Dr. Harvey if he had finally finished his research on Einstein s brain. Harvey s response was, No concrete plan. I have my ideas about it but they have not solidified. Science magazine wrote, Harvey possesses small fragments of the brain, but declines to say exactly where they are now stored. Einstein s estate, he says, has no interest in them. ... 

I. 81 for 3000 kg of ammonia gelatin dynamite. The higher the barricade, the better it inhibits the blast force and flying fragments. The fragments of brick magazine were finer (the radius of the blast was shorter) than those of the concrete magazine... 

---