what is hydrostatic stress in concrete?
912005
It is the fluid like stress before it hardens.  It is important for use in designing form works so they don't blow out.  It is more than double that of water.
272188
In its simplest form, concrete is a mixture of paste and aggregates. The paste, composed of portland cement and water, coats the surface of the fine and coarse aggregates. Through a chemical reaction called hydration, the paste hardens and gains strength to form the rock-like mass known as concrete.
347282
The concrete formula has a very low "slump".  "Slump" is a measure of how much the concrete will move while its wet.
171049
It doesn't have one. Young's Modulus is a material property relating stress and strain of a solid during elastic deformation. Water is a fluid and fluids don't "deform"; they take the shapes of their containers.
745022
Stress or load bearing means the part is subjected to mechanical or other kinds of loads.
290650
There are several types of tests for testing the strength of concrete in various ways but the most common is the compressive testing.\n\nASTM C 31/ C31M-03 allows for three different sizes of cylinders (first number is diameter): 4"x8" (100mm x 200mm), 6" x 12" (150mm x 300mm), and 9" x 18" (225mm x 450mm). They have to be prepared in a very specific manner, they are to be filled in equal layers (the number of which dependent upon the cylinder size) and each layer rodded 25 times.  After the first layer all subsequent layers should have the rod break about 1" into the layer below it.  Here's the number of layers each size cylinder requires: 4"-2 layers, 6"- 3 layers, 9"- 4 layers.  On the top layer you have to heap it over the top before rodding and if it falls below the top you have to stop and add more concrete then continue rodding.  After that you strike the top off flat and put it in a safe place.\n\nFor compression testing of cylinders you'll refer to ASTM C 39/C 39M.  Basically you have to use either a steel cap with neoprene padding or a bonded cap that is messy and stinks to high heaven when being applied.  You have then zero the machine and start applying load.  You can either run a metered advance all the way or you can apply load at an increased rate up to 50% of the design strength.  The loading rate has to be between 20 psi/second and 50 psi/second.  Some bodies have a tighter requirement of say 35 psi/s +/- 7 psi/s.\n\nAs far as running the machine if it's digital you'll have a scale that says "pace deviation" you will want to put it on the zero there during the second half of the loading, be gentle in your adjustments otherwise you risk having one break with no warning.  Once you get it in the middle it should stay there till right before the cylinder goes, it will start moving to the minus side and lower the loading rate.  You are not supposed to continue adjusting it during this phase, you have to let the cylinder fail (or you can stop it right before it goes off the minus side of the scale to avoid having to clean up a mess).\n\nIf you're using a newer machine you can hit "stress" and it'll tell you the PSI or you'll have to divide the pounds of force applied by the area of the top of the cylinder (Pi r^2) to get the pounds per square inch.\n\nHow violent the concrete fails will be dependent upon the strength of the concrete.  A 4000 psi concrete doesn't make much sound... an 8000 or 9000 psi concrete sounds kinda like a gun going off and can send stuff flying across the room.  The machine i used this summer i blew the door off of on atleast 3 seperate occasions and on one of those it sent a good sized chunk of concrete flying about 15 feet across the room.
200316
If this is what I am thinking it is, (a void in the tensioning tendon duct of a pre-stressed concrete member in a bridge), then I would suggest one of two methods;  A) a Non-Destructive Inspection (NDI), which is a kind of X-Ray to look into the concrete to find the void (will show as a shadow), or B) if you know where the void is, and you need to repair it, drill a hole perpendicular to the void, deep enough to reach the void, and fill it with a very hard epoxy resin.
1117719
Smooth concrete - elastic collision!!!\nThe total kinetic energy of the system remains the same before and after the collision, (though some deformation and loss of kinetic energy takes place).  If you hear any two object colliding, that means that some kinetic energy has been lost to the system.  The ball will transfer some of its kinetic energy into the rubber pad therefore having a significant decrease in speed.  Therefore, the ball will bounce more if dropped on the smooth concrete.
386178
Below.\nWhy?\nBecause at 100ft above water you only feel the air pressure there. While at 100ft below water, you feel both the air pressure ( strictly spreaking in physics ) plus the water pressure there.\n\nAlso, note that water is more dense than air. This means for each space, water exerts more pressure compared to air for that same displacement of space.\n\nFurther, pressure that we feel is created due to the displacement of water or air moleculs respectively by the object. So, neighbouring air/water moleculs try to "displace out" the object that caused the "imbalance" where originally there were only air/water moleculs before the placement of the object.
723118
YOUR DEALING WITH SALT WATER SO A DERIVITIVE WOULD BE ANTI AGRESSION TO THIS  SOME CONCRETE COMPANIES MAY HAVE THIS TRUE ANSWER\nANTI CORROSIVE PROTECTANT \nSEE IN FLORIDA WE USED A ALUMINUM BASED METAL BUT CHECK WITH THE CONCRETE MANUFACTURES IN YOUR AREA
748177
Shear stress, wind loads, dead loads, compression...I think.
280266
Force exerted on a material can cause stress and strain.  If you apply hand "pressure" to a glob of J-ello it will cause "stress" and deformation "strain."  If you set a weight on a surface, the force of the weight will cause "compressive stress" as it compresses the molecules of the surface that must strain slightly to bear the added force.  If you suspend a heavy magnet from a steel surface it causes "tensile stress" from tension that causes slight strain in the surface to support it.\n\nIf you take say a one square inch rod and press it down against a surface with a force of 100 pounds, the stress in the rod will be 100 PSI (pounds per square inch) compression and the stress on the surface will also be 100 PSI compression.  However, the force within the surface will become better distributed away from the contact point and the local stress at any such point will be less than 100 PSI.  Therefore, the cause and effect are both measured in PSI but depend for value on the distribution of the stress.  Although stress is calculated or measured in PSI the area in question may be much larger or much smaller than a square inch (like driving a car 60 MPH regardless of how long the trip is?).  Hope that helps a little.
768046
its basically how u see the question.\nin fluid dynamics, eq of continuity specifies that a*v = constant so with inc in area, velocity decreases,hence pressure increses\n\nwhile in solids, the case is not the same , pressure = force/area hence assuming force constant with inc in area, pressure must dec
217588
Liquefaction occurs when the structure of a loose, saturated sand breaks down due to some rapidly applied loading. As the structure breaks down, the loosely-packed individual soil particles attempt to move into a denser configuration. In an earthquake, however, there is not enough time for the water in the pores of the soil to be squeezed out. Instead, the water is "trapped" and prevents the soil particles from moving closer together. This is accompanied by an increase in water pressure which reduces the contact forces between the individual soil particles, thereby softening and weakening the soil deposit.  \n      Observe how small the contact forces are because of the high water pressure. In an extreme case, the porewater pressure may become so high that many of the soil particles lose contact with each other. In such cases, the soil will have very little strength, and will behave more like a liquid than a solid - hence, the name "liquefaction".
1055779
1 ksi = 1000 psi\n\nWhat do your points represent and how did you get that answer?\n\nLater...\nE= stress * length/deflection, or force*length/(deflection*area)\nIf the tester was zeroed, your result is non-linear - .004 deflection for the first 150# and .006 for the next 150#. Could indicate yielding - or slipping. If you're sure of your work, check the data and the setup.
947584
Within the elastic limit of any material it is seen that the stress in the material is directly proportional to the strain. \nHence the constant for the proportinality is called Youngs Mdulus (E). The unit of Youngs Modulus is N/mm^2 or MPa(Mega Pascals) or PSI(Pounds per sq. inch) same as the unit of stress.\n\nAlso it may be referred as Stress/Strain= Youngs Modulus.\n\nUsage of youngs modulus:\n----------------------------------\nStress is not a straight measurable quanitity, but engineers are very curious to evaluate stresses in a loaded material to check if it can withstand the design load or applied load. Strain is a measurable quantity (strain gages can measure strains) and once strain is measured the stress can be deduced by multiplying with the youngs modulus.
1126388
Surface tension and elasticity of the water are just about the same thing, for all practical purposes. The water can not get out of the way fast enough to let the stone sink before the motion and deflection cause the stone to bounce. The gyroscope motion of the stone is what gives it enough balance to not lose much of it's momentum when it hits something, like water. That's why flat, smooth stone work best.