Hollow Concrete Block Production And Quality Control (A Case Of Adama Town)

Abstract

HCB is one of the most popularly used wall construction material in Ethiopia as well as Adama Town. This project study the types of materials used the production process and the quality of HCB product in Adama town by randomly selecting 30 producers of HCB for interview and observation and suggest quality controlling and improvement mechanisms. The quality of the product is depending on the quality and type of ingredient material used and the production process. This study shows:- The type of ingredient material used, the production process, and the quality of the final product of HCB in Adama town is not as per the desired Ethiopian standard recommendation. The proportioning of the raw materials is recommended to be using standard measuring boxes with specified dimensions in the Ethiopian standard, but the proportioning by the respondents is using wheelbarrow which is much greater than the measuring boxes recommended. The mixing is recommended to be done only using mixer in the standards but only 13.3% of the respondents produce using mixer, the rest 86.7% are using hand mixing. Ethiopian Standard recommends for manufactured blocks on the site shall be cured in water tank or a curing yard by being kept thoroughly moist with water for at least a period of 7days or for 14 days by watering at least 3 times a day. But Only 30% of the producers cure the blocks for 14 days or more. The class of HCB product in Adama town is unknown and sub-standard. Among the compressive test conducted the maximum compressive test result attained is 7.52 kg/cm2 (0.75MPa), which is much less than the recommended for class C, which is 20kg/cm2 (2MPa). This much difference is occurred due to the absence of controlling body on the material selection, production process and the final product ready for sell. There is no controlling body on the type and quality of ingredient materials used, the production process as well as the quality of HCB produced in the town. No test is conducted on the ingredient materials as well as the produced HCB. There should be quality controlling body and quality control manual and system from the town administration for the conformance of the quality of the product.