TOWARDS UNCONFINED COMPRESSIVE STRENGTH OF CEMENT STABILIZED MASONRY BLOCKS – EXPERIMENTAL STUDY

Abstract

Cement stabilized masonry blocks (CSMB) prepared using brick powder (BP) and fine recycled concrete aggregate (FRCA) with 8% cement as stabilizer are considered as sustainable building material. Nevertheless, the geometry of the units has a significant effect on the compressive strength due to platen restraint. To arrive at unconfined compressive strength, an experimental study has been performed on both CSMB units (by varying the aspect ratio), as well as on masonry triplets. CSMB units of size 190X90X90mm and 290X90X90mm conforming to IS 1725:2013 were casted and tested in horizontal and vertical orientation. The compressive strength of 190X90X90mm is higher than that of 290X90X90mm in horizontal orientation even though the aspect ratio remains 1. The compressive strength decreases when it is tested in vertical orientation with increase in the aspect ratio. To reduce friction, 2mm thin rubber films were introduced, which reduced compressive strength by 39%. The compressive strength of the CSMB units was also assessed as per the RILEM recommendations 164. The compressive strength is similar to that of the CSMB units of size 190X90X90mm, when tested in vertical orientation. Further to affirm this, a masonry triplet of height 290mm were tested, and the results are found to be very close to those of the CSMB units of size 290X90X90mm, when tested in vertical orientation. The study concludes that, CSMB units capped with rubber film and the RILEM test procedure is more appropriate method to arrive at unconfined compressive strength.

Keywords: Cement stabilized masonry blocks (CSMB), Aspect ratio, unconfined compressive strength, RILEM recommendations 164.