Efficiency of the Use of Materials of Concrete Block against Rubble Stone on Shallow Foundation Works

Abstract

Shallow foundation work with rubble stone material has several weaknesses, such as surface and shape irregularity and scarcity in a certain location. These weaknesses can be avoided through the use of concrete block material as a positive contribution for this research. This article provides the efficiency in the use of concrete blocks instead of rubble stones in shallow foundation work, by highlighting work productivity and total cost of work for both materials. Data is collected on a wall fence foundation work which implemented both materials successfully in Grogolan, Umbulmartani, Ngemplak, Sleman Yogyakarta Province. This research has revealed that the average productivity on concrete blocks and rubble stones is 0.799 m3/h and 0.590 m3/h respectively, in which there is a time efficiency that concrete block construction is 35,44% faster than that of rubble stone. Total cost of concrete block will be more expensive than rubble stone if the work volume is small, nevertheless it reaches a break-even-point at work volume of 11 m3, meaning that a cost efficiency of concrete block construction occurs if the work volume is more than 11 m3. Moreover, the implementation of concrete block has 4 intangible benefits i.e. saving space usage, minimum waste, ease of work, and more precise product.