Comparative Study of Concrete Hollow Blocks with and Without Rice Husk Powder as Partial Replacement to Cement

Rapid development leads to a high demand and increased price for the basic
construction materials like cement. This led the researchers to look for possible partial cement
replacement by investigating the potential use of rice husk in making concrete hollow blocks.
The researchers created concrete hollow blocks (CHB) at three different percentage of rice husk
(RH) powder addition from 0%, 5%, and 10%. This study was intended to evaluate which
works best in terms of compressive strength and density. The researchers created a total of 36
samples but only 12 were tested at ASTEC Materials Testing Corporation. Cost analysis,
compression testing, and measuring of dimensions are the methods used to gather data. Results
from the testing show that the mean compressive strength of the normal CHB (0%) is 76 psi
compared to only 53 psi and 39 psi for CHB with 5% and 10% RH, respectively. The density of
the normal CHB is 1.4319 g/cm3 while 1.2497 g/cm3 and 1.2822g/cm3 for CHB with 5% and
10% RH, respectively. In the cost analysis, the normal CHB costs ₱11.58 per piece, for CHB
with 5% RH is ₱11.48, and for CHB with 10% RH is ₱11.37. Since the compressive strength of
the normal CHB is greater than that of the CHB with pulverized rice husk, the researchers have
concluded that a CHB unit is stronger and more resilient than a CHB with pulverized rice husk.
Likewise, the mean density of the normal CHB is also greater than that of CHB with rice husk
powder, it can be established that a CHB unit is more compact and rigid than the alternative.
However, the addition of rice husk powder decreases the cost of CHB, therefore, CHB with RH
is a more economical buildingmaterial.