For compressive strength, it was discussed in the previous section that a higher POFA replacement was related to a weaker bonding in the masonry blocks due to possible limitations in chemical constituent in cement. A similar reasoning may also be applied here as the breaking load decreases with the increase in POFA content. Cracks or failure for breaking load happens at a location of weakest bond. Therefore, the mixing process for masonry block production is very important to ensure proper blending between the POFA, cement and aggregate. Unbalanced spread of these materials will result in weak spots which could lead to cracking and consequently, a lower breaking load.