Characteristics of Cement Stabilized Masonry Blocks Prepared from Brick Masonry and Concrete Waste - Experimental Study

Abstract

This experimental study deals with utilization of brick masonry and concrete waste in preparation of cement stabilized masonry block(CSMB). Brick masonry waste and concrete waste are crushed into granular form and designated as brick powder (BP) and fine recycled concrete aggregate (FRCA) respectively. BP and FRCA are used in 70:30 proportions and cement content is varied as 6%, 8%, and 10%. The static compaction method is used to fix the optimum water content as 16% for all the three mixes. The size of the CSMB units is 190×90×90 mm and it is tested for dry density, wet compressive strength, water absorption and rate of moisture absorption. Correction factors reported in the literature are used to arrive at uniaxial compressive strength. The compressive strength of CSMB units of size 190x90x90 are found to be in excess of 3.5MPa, except for 6% cement content, with correction factor = 0.58. A simple equation is proposed to compute the representative 28 days wet compressive strength of CSMB units without correction factors as f = 0.8 C, with C as % of cement in the mix. The water absorption of CSMB units are within permissible limit of 18%. The rate of moisture absorption of the units is found to follow an exponential trend. Nearly 50% of absorption is found to take place in the first 30 mins of soaking. To study the influence of size, CSMB units of size 290x190x90 mm with 8% cement are cast and wet compressive strength is determined on the cubes 70 mm and 90 mm cut from the CSMB units 290x190 x90 mm, as well as, on the units also. The 70 mm and 90 mm cube samples cut from CSMB units show a decrease of 32% and 35% in wet compressive strength when compared with 70.6 mm cube samples cast from the same mix. The 28 days wet compressive strength of CSMB units 290 x190 x90 mm with aspect ratio as 0.47 is about 70% more than the strength attained with units 190 x90x90 mm with aspect ratio as 1.0.