Compressive Strength for CLSM 1

[btv189]

We are using a 250 psi mix for flowable fill, and we came back and cored a placement and tested a 90 day strength and the material had increased from the 250s to 1200-1400 psi, what could be some reasons for this massive gain in strength?

 

[fattdad]

how was the mix design established?

f-d

¡papá gordo ain’t no madre flaca!

 

[DDBPE]

In my experience with flowable fill in eastern US, there were two types, excavatable (meaning it could be dug up with hand tools or light equipment) and non-excavatable (meaning larger equipment would have to be used to dig it), if you had to remove it. From the psi indicated, it would appear you have a non-excavatable mix.

I agree with fattdad, you would need to review the mix design.

 

[btv189]

the mix design was developed by trial batching, includes 80 lbs of cement, air, water, and fine aggregate. The material was developed to be excavatable but there is concern about the strength because it is being used to cover a pipe line with the concern being related to seismic activity.

 

[dik]

From my General Notes:

Format may require adjustment...

TYPE OF CONST CEMENT MIN F'c MAX SIZE MAX AIR
TYPE AT 28 DAYS AGG SLUMP
(MPa) (in) (in) (%)

CLSM GUb 0.7 3/16 10 4-6

CLSM GUb 1 3/16 10 4-6

CLSM GUb 2 3/16 10 4-6




CLSM TRIAL MIX PROPORTIONS

MIN CEMENT 50 PCY
MIN FLY ASH (TYPE F) 150 PCY
FINE AGGREGATE 2700 PCY TO ASTM C33
MAX WATER 290 PCY

FLYASH SHALL NOT HAVE A HIGH ALKALI, SULPHATE OR REACTIVE MATERIAL CONTENT

Dik

 

[cvg]

250 psi is way too high

we typically require 1/2 sack, 25 psi minimum and 100 psi maximum at 28 days for diggable. long term strength gain (90 days) is probably due to fly ash in the mix

 

[dik]

Then you spec the 0.7 MPa... about 100 psi... some are hand excavatable (sp/word ?) while others are light excavator...

Dik