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I'm assuming here that all materials will have a change in elasticity due to thermal expansion/contraction and a resultant reduction/increase in the strength of the bonds of the atoms leading to a varying young's modulus. But how significant is it (at normal non-extreme ambient temperatures - maybe from -10°C to 50°C)?

If anyone know's of any research into this. Or even a table of values like the following, that would be very useful: http://www.engineeringtoolbox.com/young-modulus-d_773.html

The reason I am asking is I am interested in Structural Health Monitoring, and I've read a lot of researchers claim that temperature has a major impact upon structural stiffness due to changes in material stiffness. I'm yet to find substantial evidence of this.

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  • $\begingroup$ Don't the charts that you link to show that there is very little change in modulus in the temperature range that you are considering? Also, think about how it may be impossible to make a general statement about the two materials that you mention (concrete, asphalt) since there are many different mixes of each and the workmanship also affects it. Even the chart that you link to had separate lines for steel composition. $\endgroup$ – hazzey Feb 8 '17 at 14:19
  • $\begingroup$ Concrete probably doesn't change too much over a narrow range, but asphalt may. Asphalt is a ceramic aggregate reinforced polymer (effectively). The polymer (tar pitch?) probably has mechanical behavior strongly dependent on temperature, specifically across its glass transition. Generally there is a 2-3 order of magnitude decrease in elastic moduli heating above the glass transition for traditional polymers. I am speculating outside my area of expertise here, but based on my understanding, and assuming asphalt behaves similarly, it would flow more readily above its Tg. $\endgroup$ – wwarriner Feb 9 '17 at 17:00
  • $\begingroup$ From this article: ems.psu.edu/~radovic/1985/papers/1985_168.PDF, it appears coal tar pitch has Tg between about 40 and 45 C, which is within the desired range of the OP. I would expect a change from close to 1 GPa at -10C-35C, to 1 MPa close to 50 C. Again I am speculating, I don't have evidence to support the claim other than well-known info from related materials. $\endgroup$ – wwarriner Feb 9 '17 at 17:03
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    $\begingroup$ Thanks people! The link I put in the description shows the relationship for different types of steels and other metals, I'm specifically looking for the effect of temperature on pavement materials. I've continued researching and I've found a few different sources. As you noted @starrise there are heaps of kinds of HMAs and other pavement materials, so the results I have found are very varied. But I think you're right about the 'glass transition'. Many of the sources I found show an exponential relationship with HMA stiffness and decreasing temperature. Crazy! I might answer my own Question $\endgroup$ – Noobie Feb 10 '17 at 1:31
  • $\begingroup$ Amoco did more testing of bituminous concrete ( aka asphalt pavement) than anyone. The problem is that it is all over 50 years old and I doubt any is on the web. Much testing on various asphalts, resins and oils ( the components of "asphalt") at various temperatures. Author names - Robert Marshner , Art Sisco,, Hopson, Larry Brunsen ; a technical literature search should turn up something .When the Arab oil embargo raised oil prices in 1973 , asphalt R&D stopped because customers were happy to get any asphalt mix they could . $\endgroup$ – blacksmith37 Sep 8 '18 at 20:22
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For concrete and asphalt, you would be more interested in the properties of creep, which is always a function of temperature. For example, there is an entire wikipedia page about this at this time, which mainly references ACI Committee 209

For polymers, there are many models for creep. Due to the extensive range of polymer chains, it would be difficult to model a general version without testing some asphalts specifically.

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The modulus of elasticity is not going to significantly change for concrete in ambient temperatures but there are provisos.

The assumption is that you are talking about set concrete that has achieved 28 day strength. If you are talking about fluid concrete then that is down to the slump test and results are highly variable between strength types.

High strength concrete hardens rapidly and more so in higher temperatures. Obviously low temperatures will affect crystal lattice formation and ice would interfere with the rate of formation which is why ice is added to high strength concrete on sites in hot countries while being poured.

If you want to find out the effects on elastic range then an extensometer test would be the best way to find out the thermal effects. That said, concrete is not terribly good under tension so the results will likely be quite inconclusive. A Charpy test would demonstrate energy absorption and therefore the compressive variation but again the issues you face are that concrete is highly variable in composition and quality control is very limited, unlike steel which is manufactured to a much higher quality and far lower variability of structural properties during manufacture.

The thing about tons modulus and concrete is that 5% of specimens will achieve maximum strength, 10% expected to fail strength and the rest will be median strength within allowed safety limits and thus modulus of elasticity is accounted safe within legislated limits.

You may find more on the subject through Eurocode specifics in various text books on the subject.

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