Recycling Fine Aggregate from Demolished Hollow Concrete Block for Green Concrete in Ethiopia

Abstract

As a result of a change in the living standards and an accelerated rate of urbanization, the construction industry is booming globally.The construction industry is among the most prosperous economic sectors around the world as it transforms various resources into the constructed infrastructure necessary for socio-economic development. Despite the relevance to the socio-economic growth, it's also recognized that construction activities and the natural environment are interconnected [1]. Lately, waste generation due to demolition has become an essential issue with possible negative impacts on the environment. There is a large amount of construction and demolition (C&D) waste generation due to: new zoning bylaws, modified settlement patterns, increased population in urban areas due to industrial development, modernization of old road, and bridges for the present as well as for future growing traffic, and during renovation and demolition of existing buildingEthiopia is experiencing problems, of rapid population growth rate, lack of education amongst the population, uncontrolled rapid urbanization, affordable housing shortages, and erosion. Along with most of the African cities, Ethiopian cities don't have the spatial, physical, and socio-economic requirements fundamental to sustain the livelihood of the city. To address the problems, the Ethiopian government has been implementing transformation plans and low -cost housing programs [3,4]. These programs were launched during different phases according to the agreements reached such

Comparative Investigation of the Effect of Recycled Fine Aggregate from New and Old Construction Wastes in C-25 Concrete in Ethiopia

“…This indicates that Ethiopia is behind on the recycling of construction and demolition wastes. However, for the last seven years, some research [4,11] was undertaken on the recycling of construction and demolition wastes. Woubishet [4] assessed the suitability of recycled aggregate in concrete and the effect of recycled concrete aggregate on concrete properties.…”

“…The researcher concluded that the physical properties of recycled concrete aggregate had fewer physical properties than the original aggregate but was within the required standard limit. Lucy et al [11] investigated the recycling of demolished hollow concrete blocks as fine aggregate in concrete. The physical properties of recycled fine aggregate and the effect of replacement of natural sand by recycled fine aggregate on fresh and hardened properties of concrete were investigated through local technology and methods.…”

“…For the coarse aggregate, locally available crushed stone aggregate with a nominal size of 20 mm was used. The specific gravity, water absorption, and fineness modulus properties of coarse aggregates were checked as per the ASTM standard [11]. The coarse aggregate used in this experiment is well graded.…”

“…There were two types of sand used for this research work, locally available river sand and recycled fine aggregate. The local river sand used was checked for silt content, gradation, absorption capacity, moisture content, unit weight, and bulk specific gravity as per ASTM standards [11].…”

“…The physical properties of recycled fine aggregate, silt content, sieve analysis, unit weight, 181 moisture content, specific gravity, and water absorption were tested as per the ASTM standard, and 182 the results are summarized in Table 1. For river sand, the silt content was within the required limit 183 at less than 6% [11], but the silt content of recycled fine aggregate from construction HCB was washed 184 to attain the limit. The cement powder from HCB and fracture dust during crushing was the cause 185 for high fine particles that passed through the 150 µm sieve size.…”