Compressive strength vs. durability 2

[CTW]

Is there a reference or publication relating compressive strength to durability or wear resistance? Maybe a chart or graph? For instance, how much more durability or wear resistance can be attained by using 4 ksi, 5 ksi, 6 ksi, etc., concrete?

 

[BigH]

I'll get back to you after I check Neville's tome. Still, the old Canadian Standards CAN3-A23.1.M77 has, in Appendix E a note on Abrasion Resistance of Concrete Surfaces. I'll try to reproduce here. The "number" is the Depth of Wear in mm after 10 test cycles.

A: steel trowel - 1 pass : 5
B: steel trowel - 2 passes: 4.4
C: float finish subj to immediate curing: 5.7
D: as per A. plus cement: Sand (1:1.5) Shake at 6kg/m2 -
4.4
E: as per B. plus Cement:Iron (1:2) Shake at 7.2kg/m2 -
1.7
F: as per A. with curing delayed 24 hours: 8.3

Further, they have a graph showning compressive strength and depth of wear in mm after 10 cycles:

for 10MPa: about 9
for 15MPa: about 6.5
for 20MPa: about 5
for 25MPa: about 4
for 30MPa: about 3
for 35MPa: about 2.2
for 40MPa: about 2

As well, curing has an effect (no mention of comp. strenth)

for w:c ratio of 0.5:

3-day moist curing: 4.5
7-day moist curing: 3.7
28-day moist curing: 2.5

for w:c ratio of 0.4:

3-day moist curing: about 3
7-day moist curing: about 2.2
28-day moist curing: about 1.8

for w:c ratio of 0.6;

3-day moist curing: about 6.5
7 day moist curing: about 5.5
28-day moist curing: about 3.5

The "cycles" is of some German test. It is referenced as:

Sawyer, James L. "Wear Tests on Concrete Using the German Standard Method of Test and Machine", ASTM Proceedings, Vol 57, 1957, pp 1143 to 1153.

CDN Standards also state (section 22.5.3.2: "The main purpose of additional trowelling is to increase compaction of fines at the surface, giving it greater density and wear-resistance. The final pass of the trowel should produce a clear ringing sound.

There may, obviously, be more recent material - but this may get you started.

 

[sdz]

There is a general relationship between concrete strength and durabliy and wear resistance. Higher strength concrete can be expected to perform better than low strength concrete, although there are many influencing factors.

For convenience and for want of a better measure the Australian code AS3600 uses concrete strength as a measure of durability (protection against corrosion of reinforcement) and wear resistance.

E.g. strength requirements for abrasion
Footpaths and residential driveways - 20MPa
Commercial and industrial floors not subject to vehicular traffic - 25MPa
Pavements or floor subject to:
Light pneumatic tyred traffic < 3T gross mass - 25MPa
Medium or heavy pneumatic tyred traffic > 3T gross - 32MPa
Non-pneumatic tyred traffic - 40MPa
Steel wheeled traffic - to be assessed but not less than 40MPa

 

[CTW]

I'll have to look into the German wear test to see what was used to perform the test. But the info given is useful.

Most publications I read stipulate that there is a relationship between compressive strength and durability. This is understandable. I guess what I'm ultimately after is for a slab under constant scrapping and/or heavy truck traffic, is 6000 psi concrete going to provide the wear resistance necessary (increased life) to justify the added cost vs. the wear resistance (life expectancey) of 4000 psi concrete.

 

[sdz]

In that situation I would look at using steel fiber reinforced concrete. That is what I used recently for some load out slabs and bunkers where wheel loaders would be operating. I still specified 40 MPa concrete.