Field Mortar Testing 1

[mgardina]

I have a technical question regarding quality control for field mortar. ACI 530 suggest ASTM C270 (but this requirement only applies to laboratory mortar) or ASTM C780 (does not indicate strength values only procedure). Does anyone know the real way to ensure quality mortar at the job site?

Thanks.

 

[Ron]

The best way to get quality mortar on the job is by inspection. Testing has historically caused more controversy in mortar quality than it has provided answers.

I am a proponent of using C780, as there are numerous issues with using C270 as a field testing method. I also feel that compressive strength is an appropriate acceptance parameter for mortar (contrary to the mortar cement suppliers!), provided the testing is properly done (using 3"x6" molds, field protection, proper laboratory testing, etc.

Proportion specifications will work, but they don't correlate consistently with compressive strength. Though safety factors can be high in masonry design, as an Engineer I prefer quantification of mechanical properties, not just warm, fuzzy feelings!

 

[testman]

WHEN TALKING WITH PEOPLE OVER THE LAST FEW YEARS I HAVE BEEN TOLD THAT MAKING TEST CUBES ALONG WITH CHECKING THE INPLACE STRENGTH USING THE ASTM C803 RESISTANCE TO PENETRATION PIN TYPE IS A GOOD WAY TO ENSURE THE QUALITY OF THE MORTAR AT THE JOB SITE.

 

[clarkson]

not being familiar with north american parlance iam assuming that we are talking about masonry mortars. the best method i have seen for producing consistent quality is having the mix delivered in silos which cuts down on wastage and theft also. a uk company called cpi mortar does this..im sure they will have a web site. if we are talking of concrete then an interesting article i read told of a company in london (st george i think) who cast bolts into their slabs and conduct a pull out test after 'x' days