what is the relation between compressive strength ,density,resistance in concrete?
931774
.  I do not know what you mean by resistance.  It is something I have not heard of measuring in concrete.\n.  There is no meaningful relationship between compressive strength and density.  Concrete all comes out to about 145 to 150 pounds per cubic foot, for ordinary concrete, less for light weight concrete, which is made light weight by using porous aggregate.  Lightweight concrete, depending on the mix designs, can be stronger than normal weight concrete.\n.  The strength of concrete is determined by the cement content.  The cement is not the same thing as concrete.  The cement is the stuff that makes it all stick together.  Concrete also contains sand gravel, rock dust and water.  Too much water weakens the concrete by reducing the density of the crystals which grow from the cement as the concrete sets.\n.  The strength of the concrete is also affected by the quality of the cement.  A concrete batch plant has to make trial samples with every delivery of cement to determine how much cement has to go into the mix to achieve a certain strength.  I will vary form one cement delivery to the next.
599986
10"x16"x24" Poured concrete wall\nLoad = 711,000 lbs\nGross Strength = 4670 PSI\n\n10"x16"x24" Block wall\nLoad = 164,500 lbs\nGross Strength = 1580 PSI\n\nSo it would seem the following:\nPoured is ~ 295% stronger than block\n\nPlease see the sources below for more information
576519
tensile strength = (2*P)/(pi*t*d)\nwhere; P =maximum load you get from the machine(kPa); pi = 3.14; t = thickness/height of specimen (m) and d = diameter of specimen(m)
807934
Typically when a material is refered to as strong, you are refering to its mechanical property can 'Tensile Strength' - How much force you can pull it with before it breaks.\n\nIt terms of what makes one material strong compared to another, is related to many factors - On a microscopic level, basically how easy it is for discontinuities in the material to move.\n\nWith reference to your concrete example, the reason concrete of a skyscraper is strong, primary is because it is steel reinforced; steel bars are embeded inside the concrete - The combination of steel and concrete is a good one because steel is very strong in tension (which concrete is not) but concrete is very good in compression.\n\nWhen you combine different materials like this, the resulting material is refered to as a composite. Composites presently are the best structural materials that we have; examples are fiberglass/polyester and  carbon/epoxy. Carbon/epoxy is extremely popular for aerospace structures because of its high strength and low weight, as well as its durability. When composites first appeared, they were very expensive and limited to really hi-tech applications like aerospace, but today you can find them everywhere - golf club shafts are commonly carbon/epoxy for example.
1097722
Steel is stronger, in both tensile and compressive strength. Chalk crumbles.
136019
Depending on location, local building code and sizemic zone.\n By deffinition, the amount of conctete that is measured from the center of the reinforcing steel to the edge of concrete, "cover" references covering the reinforcing.
76587
It is the Concrete in which heavy aggregate is used to increase the density of the concrete; unit weights in the range of 165 to 330 pounds per cubic foot are attained.\n\nHeavy weight aggregate is an aggregate of very high unit weight, such as barium, boron, or iron ore, steel shot or punchings, which forms a high density mortar of concrete when bound together with hardened cement paste
252653
The hammer must be calibrated with a compression test cylinder or a flexural strength break on the same batch of concrete that it is used. Once the hammer is calibrated, it works by measuring the penetration of a rod pushed into the surface of the concrete at a known repeatable force. The greater the penetration of the rod, the less the strength of the concrete. Think of it as pushing your finger into mud. The stiffer the mud, the less you can push your finger into it.
688085
density it mass per volume.\nlitre is a measure of volume.\n\nvalidity is not a physical quantity.
1073782
These numbers refer to the compressive strength gained by the cement-sand mortar mixed in the proportion of\n 1:3   with\n (p/4 + 3)% of water of the total mass.\nThe mortar so obtained is caste into cubical moulds of 70.5mm side ie 5000mm2 area and cured for a period of 28 days and then tested in a compression testing m/c.\nThe grade of any cement sample is an assurance of the fact that the compressive strength as determined with the help of the above mentioned test will be atleast equal to it.
583234
bulk density /(moisture content - 1) is equal to dry density.\n\nBulk density = weight of wet soil collected from the hole / volume of the hole\n\nVolume of hole = wt. of sand transferred into hole / bulk density of sand\n\nWeight of sand = Total wt of sand in cylinder before pouring - (wt of sand in cylinder after pouring+wt of sand in cone)\n\nBulk density of sand and wt. of sand in cone are determined in laboratory. for details on that write to nobodyat34@yahoo.co.in
1011938
Resistance does not depend upon the ductility of the metal used in the wire.\nDuctility is the property of the substance to be easily drawn into wires.  This does not effect electrical resistance.
846443
Density is simply mass per unit volume.  The density of a substance is directly related to the atomic weight of the element composing it, ie., elements with higher atomic weight can be thought of as being “heavier”.   Another way of stating this is that equal volumes of two different substances have different densities because each different substance has a different mass (ie, atomic weight) and crystal structure.  There are many types of units which can be used to measure the mass of a substance (pounds, grams, etc.), just as there are many types of units which can be used to measure volume (cubic feet, cubic centimeters, etc.).  The standard units of measure for density are grams/cubic centimeter.  \n\nDifferent minerals or rocks can vary greatly in density, depending on their chemical make up.  Density is such a characteristic property of a substance that it may be used to identify the substance.  Geologists have found it useful to develop a system of comparing densities of different minerals or rocks by calculating a numerical value without units known as “specific gravity”.  The specific gravity is the weight of a substance compared to an equal volume of water.  Water is chosen as the substance for comparison because by definition it has a density of 1 gram per cubic centimeter (at 4o C), and also because it is such a common substance.  For example, compare the density of a rock like granite to water:  a cubic foot of water weighs 62.5 pounds and a cubic foot of granite weighs 168 pounds.  The specific gravity of granite is:   168 / 62.5  =  2.7.   Granite is 2.7 times heavier than water.
489536
By strength I suppose you mean elastic calculation when the body is subjected to deforming forces. Actually, the centroid of a shape having an unifrom mass distirbution coincides with its center of mass. This point is central to the analysis carried out in rigid body statics and dynamics.
904405
Yielding is when a material deforms plastically, that is when you bend it it will not recoil to its original shape.  Strength to weight ratio is merely a value given to a material that describes its ability to withstand force related to its weight or density (for example an airplane would want a lightweight material that is very strong).  Lastly a point load is a load that a force is being applied in one specific loaction, in reality this is impossible but when contact areas are very small we assume them to be point loads.  A distributed load is one where a force is applied over a given area.  A person generates a distributed load on the floor over they area of their soles of their feet for example.
123120
>>Aggregates\n\nAlthough latent heat effects (heats of desorption, dehydration) are primarily determined by the cement paste, the thermal conductivity of concrete is determined by the aggregate.\n\nConcretes may be divided into two major groups: normal weight concretes (usual density range: 120 to 140 lb/ft³) and lightweight concretes (75 to 100 lb/ft³). Normal weight concretes are usually made with natural deposits of gravel and sand aggregates or with crushed stone. The two main factors that determine their value in fire are their chemical stability and degree of crystalline order. Less stable aggregates, i.e. those containing large amounts of hydrated water, undergo decomposition and dehydration reactions at higher temperatures. (In general, concretes that do not show more than 5 per cent weight loss when heated from 200 to 1600°F can be regarded as made with physicochemically stable aggregates.) As these reactions are normally accompanied by the absorption of latent heat, unstable aggregates are often an advantage from a fire endurance standpoint.\n\nThe thermal conductivity of aggregates, and thus of concretes made with them, depends on both the aggregate's internal microstructure and its mineralogical composition. The conductivity of highly crystalline aggregates (i.e. those having a well defined microstructure) is high at room temperature and decreases with rise of temperature. Amorphous aggregates (e.g. traprock, basalt) exhibit low conductivity at room temperature; this increases slightly as the temperature rises.\n\nAmong the common natural stones, quartz has the highest conductivity. The thermal conductivity of concretes made with quartz aggregates may be as high as 1.5 Btu/hr ft °F at room temperature (in oven-dry condition). The lower limit for the conductivity of normal weight concretes made with other natural aggregates is about 0.7 Btu/hr ft °F. When the temperature rises, the difference diminishes, and at temperatures over 1400°F all normal weight concretes exhibit roughly identical conductivities, 0.7 to 0.8 Btu/hr ft °F.\n\nLightweight concretes are usually made with processed lightweight materials or industrial byproducts such as cinder, slag, and various expanded slags, shales, clays and slates. Less frequently, natural lightweight aggregates are used, for example pumice, scoria, volcanic cinder, tuff. Lightweight aggregates, particularly manufactured ones, exhibit high chemical stability at elevated temperatures, so that the only latent heat effects that must be considered are those associated with the dehydration of the cement paste.\n\nSince the porosity of lightweight aggregates is high and the solid matrix normally on the amorphous side, the thermal conductivity of lightweight concretes is very low, typically 0.2 to 0.4 Btu/hr ft °F at room temperature. Again, this range of values decreases at elevated temperatures and, above 1400°F, 0.35 Btu/hr ft °F is a typical value.\n\nIt is becoming more and more popular to substitute sand in lightweight masonry units for some of the fine aggregates. Typically, 10 to 20 per cent of the total aggregate volume is replaced by sand to control the porosity, strength and texture of the units, to ensure good paste-to-aggregate bonds, and to eliminate certain production problems. Lightweight concretes made with natural sand exhibit characteristics between those of the lightweight and normal weight concretes.<<\n\nThere's more stuff at the following link:
856161
By unit volume, probably dry cement is heavier. Why? Because rocks are heavier than water.