Thesis (BS Architecture) -- University of the Philippines Mindanao, June 2017

This explored the infusion of rice husk biochar (RHB) as a new component in the production of ICEBs, in this case, Interlocking Compressed Earth-biochar Blocks (ICEbB). The compressed earth-biocharcoal blocks used in this experiment mainly consists of sandy soil, cement, and charcoal. Soil being the most dominant component, make use of lesser cement content at a ratio of 1:8 (approx. 12.5% of the total mixture by weight or 0.88 kg.) charcoal is used to replace cement at 10%, 20% and 30%, which appeared to be more than cement by a volume because it is very lightweight in nature. The block sample produced were observed and assessed based on different categories such as appearance, dimensions, texture, shape and shrinkage. Mechanical properties of the block samples were determined through tests conducted namely, dry compressive strength tests and moisture absorptivity tests. Major findings based on the data gathered and analyzed suggested that in general, San Manuel soil samples with rice husk biochar as an additive component in the mixture for ICEB production performed best in the whole experiment process that those of the Tugbok soil samples. Overall, ICEB made of San Manuel soil (SMS). Also delivered best appearance based on texture, dimension and geometrical characteristics. Results on dry compressive strength test showed that ICEbBs made of earth with higher sand content and higher cement content regardless of charcoal content had best performances, San Manuel soil (SMS)-C, which is the control block sample, had the highest compressive strength at 581.818 psi and has passed all mechanical constraints except as structural elements that are not capable of withstanding high external live loads. On the other hand, for sample blocks with biochar content as an additive component, Sa Manuel soil (SMS)-2 which has 20% charcoal content by cement weight has performed best among the group. It acquired the second highest compressive strength amongst all block samples at 538.188 psi and has also passed all mechanical constraint categories except for category 3, which also limits it as structural elements that are not capable of withstanding high external live loads like the control block sample. Of all the block samples from the San Manuel group, only San Manuel soil (SMS)-3 which has 30% charcoal content by cement weight has passed all the mechanical constraint categories despite from acquiring the lowest compressive strength among the San Manuel group at 486.057 psi, which is still acceptable, according to the New Zealand Standards for Engineering Design for Earth Building) (NZL 4297) and the 2009 New Mexico Earthen Building Material Code which established a minimum strength for earth blocks at 0.5MPa and 2.07 MPa, respectively. Capillary absorption tests suggested that, despite San Manuel sample block having highest compressive strength test results, the group had highest average capillary absorption coefficient rates than the Tugbok soil samples - San Manuel soil (SMS)-C (7.290), San Manuel soil (SMS)-1 (8.023), San Manuel soil (SMS)-2 (7293), San Manuel soil (SMS)-3 (3.650). this would likely compromise strength of block samples, thus, waterproofing measures should be maximized. Based on the results delivered by the blocks in general, they are all considered non-load bearing blocks, thus structural concrete supports are needed. Also, charcoal, as one of its main components have disinfecting and odor reduction properties, and if applied as interior walls, these blocks project great potential in making an improvement in a building's indoor environment quality. Furthermore, research on higher charcoal content and different waterproofing and plastering methods are recommended for ICEB development.