Economic and Environmental Evaluation and Optimal Ratio of Natural and Recycled Aggregate Production

Abstract

Steady increase in overexploitation of stone quarries, generation of construction and demolition waste, and costs of preparing extra landfill space have become environmental and waste management challenges in metropolises. In this paper, aggregate production is studied in two scenarios: scenario 1 representing the production of natural aggregates (NA) and scenario 2 representing the production of recycled aggregates (RA). This study consists of two parts. In the first part, the objective is the environmental assessment (energy consumption and CO 2 emission) and economic (cost) evaluation of these two scenarios, which is pursued by life-cycle assessment (LCA) method. In the second part, the results of the first part are used to estimate the optimal combination of production of NA and RA and thereby find an optimal solution (scenario) for a more eco-friendly aggregate production. The defined formulas and relationship are used to develop a model. The results of model validation show that the optimal ratio, in optimal scenario, is 50%. The results show that, compared to scenario 1, optimal scenario improves the energy consumption, CO 2 emissions, and production cost by, respectively, 30%, 36%, and 31%, which demonstrate the effectiveness of this optimization.

Managerial Areas of Construction and Demolition Waste: A Scientometric Review

“…In the LCA approach, energy consumption and CO 2 emission are the two most evaluated impact categories [ 98 ]. Application of the LCA method can be classified into six aspects: environmental impacts of a building [ 44 , 99 , 100 ], environmental impacts of construction waste in the construction phase [ 101 , 102 ], environmental impacts of demolition waste in the end-of-life phase [ 103 , 104 ], environmental impacts of demolition waste in the refurbishment phase [ 105 ], environmental impacts of recycled aggregates [ 106 , 107 , 108 , 109 ], and environmental impacts under different CDW management strategies [ 14 , 110 , 111 , 112 , 113 ]. Results show that, compared with landfill, most of waste recycling and reuse methods bring net environmental benefits [ 14 , 101 , 106 , 110 ].…”

Influence of Design Parameters on Fresh Properties of Self-Compacting Concrete with Recycled Aggregate—A Review

“…Over the past few decades, there have been a lot of changes occurring in the concrete sector to traditional ways of its production, notably the addition of minerals, chemical admixture, new supplementary cementitious materials (SCM), etc. To accomplish the sustainability in the concrete production process, the following measures are to be taken: Reduction in carbon dioxide emission produced during raw material quarrying and processing [ 11 , 12 ]; Reduction in natural resource utilization [ 12 , 13 ]; Reduction in cost [ 14 , 15 ]; Enhancement of fresh and hardened properties of concrete [ 9 , 16 , 17 ]; Less energy consumption during the production process [ 18 ]; Reduction in noise level due to vibration caused by compaction of concrete [ 14 ]. …”

“…Obtaining cement-based materials made with RA (obtained from the treatment of C&DWs) has been one of the most studied applications. Although, indeed, there are currently some reliable studies that support the use of C&DW in conventional concrete [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], in recent years some studies on the use of RA have begun to be published with self-compacting concrete (SCC), although they are still rare [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Most of these studies compare the various fresh and hardened properties of SCC with RA and without RA (natural aggregates), apart from SCC mix design.…”

The Use of Volcanic Powder as a Cement Replacement for the Development of Sustainable Mortars

“…As a result, many studies have focused on reducing the environmental damages associated with its manufacturing. Several investigations have been based on one solution which is related to the study of the effects of substituting different concrete constituents with reused materials [3][4][5][6][7].…”