An Optimization System for Concrete Life Cycle Cost and Related CO2 Emissions

Abstract

An optimization system that supports the production of concrete while minimizing carbon dioxide (CO 2 ) emissions or costs is presented that incorporates an evolution algorithm for the materials' mix design stage, a trigonometric function for the transportation stage, and a stochastic model for the manufacturing stage. A case study demonstrates that applying the optimization system reduced CO 2 emissions by 34% compared to the standard concrete production processes typically used. When minimizing the cost of concrete production was prioritized, the cost dropped by 1% compared to the cost of conventional concrete production. These findings confirm that this optimization system helps with the design of the concrete mix and the choice of a material supplier, thus reducing both CO 2 emissions and costs.

Optimal Design of the Cement, Fly Ash, and Slag Mixture in Ternary Blended Concrete Based on Gene Expression Programming and the Genetic Algorithm

“…Lee and Yoon [10] presented a procedure, based on neural networks and the harmony search algorithm, for designing a concrete mixture under various constraints. Kim et al [11] proposed an evolution algorithm for minimizing a concrete’s life–cycle cost or CO 2 emissions that considers the mixing stage, the transportation stage, and the manufacturing stage. Sebaaly et al [12] proposed a technique, based on a neural network and the genetic algorithm, for optimizing the aggregate gradation and binder content in an asphalt mix.…”

“…Tapali et al [13] presented a numerical iteration method for finding the optimal concrete mixture that considers strength, carbonation, and chloride durability. However, the models [9,10,11,12,13] have some weak points. Tapali et al [13] do not consider the concrete’s workability.…”

Analysis of Life Cycle Environmental Impact of Recycled Aggregate

“…The functional unit for the life cycle impact assessment of recycled aggregate was 1 kg, and the system boundary was product stage of concrete (Cradle to Gate) [27].…”

Studies on Environmental Impact Assessment of Reinforced Concrete in Different Life Cycle Phases

“…Kim et al (2016) If concrete mix and raw material suppliers were carefully selected, it can be obtained a reduction of 34% in the emission of CO 2 and 1% in the costs Park et al (2012) CO 2 emissions increase linearly with the compressive strength of the concrete; to similar strengths, the concrete produced in the winter presented an increase of approximately 5% in the CO 2 emissions Santoro and Kripka (2016) Higher strength concrete will produce a greater amount of CO 2 ; the CO 2 emissions during transport are significant Choi et al (2016) For smaller loads the increase of the transversal area of concrete is more advantageous for the eduction of O 2 emissions, and for greater loads the increase of the steel profile produces a more sustainable solution Berndt (2015) The use of smaller resistances is advantageous in relation to CO 2 emissions; the choice of the concrete mixture strongly influences the magnitude of the CO 2 emissions Yang et al (2015) The intensity of CO 2 emissions gradually decreases as Portland cement is replaced by complementary cementitious materials (up to 20%) García-Segura et al (2014) In comparison to Portland cement, despite the reduction in CO 2 capture and life time, 80% blast furnace slag cement emitted 20% less CO 2 per year Cabello et al (2016) To reduce the environmental impact generated by a structure, the focus should be on phases of production of raw materials, transportation and production of concrete Oliveira et al (2014) It is not appropriate to base decisions on the emissions of concrete solely on the strength of the concrete and the type of cement used, since the variations are significant Paya-Zaforteza et al (2009) Minimization of embedded CO 2 emissions and economic cost seem to be highly related Park et al (2013) Reducing the amount of steel and increasing the amount of concrete can be an effective way to reduce the structural costs and CO 2 emissions of columns Habert and Roussel (2009) It is also possible to combine cement replacement and increase mechanical strength Possan et al (2016) Concrete during its life time can absorb from 40 to 90% of CO 2 emitted in the manufacturing process; the absorption of CO 2 is directly proportional to the surface area of concrete exposed to CO 2 , and influenced by the type of cement and resistance to concrete. Park et al (2014) Increasing the strength of the structural materials used is more efficient in reducing CO 2 emissions and costs than increasing the quantities of structural materials used Collins (2013) If carbonation is ignored, emission estimates can be overestimated by up to 45% depending on the strength of the concrete that was used as well as the type of construction application that incorporates recycled concrete during the second generation Yepes et al (2012) CO 2 emissions and costs are closely related.…”

“…Kim et al (2016) report that the Korean construction industry accounts for 40% of total CO 2 emissions in the country and that it is essential to reduce these quantities. In their study, they developed an optimization system to minimize CO 2 emissions and maximize the economic efficiency of concrete in the cradle-to-gate phase, that is, from the production of the raw material to the point where it leaves the manufacturer's production facilities.…”