Mixture-Proportioning Model for Low-CO₂ Concrete Considering the Type and Addition Level of Supplementary Cementitious Materials

Abstract

The objective of this study is to establish an rational mixture-proportioning procedure for low-CO 2 concrete using supplementary cementitious materials (SCMs) achieving the targeted CO 2 reduction ratio as well as the conventional requirements such as initial slump, air content, and 28-day compressive strength of concrete. To evaluate the effect of SCM level on the CO 2 emission and compressive strength of concrete, a total of 12537 data sets were compiled from the available literature and ready-mixed concrete plants. The amount of CO 2 emission of concrete was assessed under the system boundary from cradle to concrete production stage at a ready-mixed concrete plant. Based on regression analysis using the established database, simple equations were proposed to determine the mixture proportions of concrete such as the type and level of SCMs, water-to-binder ratio, and fine aggregate-to-total aggregate ratio. Furthermore, the CO 2 emissions for a given concrete mixture can be straightforwardly calculated using the proposed equations. Overall, the developed mixture-proportioning procedure is practically useful for determining the initial mixture proportions of low-CO 2 concrete in the ready-mixed concrete field.

Evaluation of the Carbon Dioxide Uptake of Slag-Blended Concrete Structures, Considering the Effect of Carbonation

“…Table 2 shows a summary of CO2 emission factors for concrete production. The CO2 emission content of 1 kg of GGBFS is 0.034 kg [1], which is much lower than The contributions of this article are summarized as follows: first, propose a slag-blended cement hydration model and calculate reaction degrees of cement and slag. Second, evaluate the carbonatable materials content and porosity using the reaction degrees of binders.…”

“…Portland cement is the principle hydraulic binder used in modern concrete. The production of one ton of ordinary Portland cement (OPC) generates 0.55 ton of chemical CO 2 and requires an additional 0.39 ton of CO 2 in fuel emissions, accounting for a total of 0.94 ton of CO 2 [1]. The word's yearly cement accounts for nearly 7% percent of global CO 2 emissions [1].…”

“…The production of one ton of ordinary Portland cement (OPC) generates 0.55 ton of chemical CO 2 and requires an additional 0.39 ton of CO 2 in fuel emissions, accounting for a total of 0.94 ton of CO 2 [1]. The word's yearly cement accounts for nearly 7% percent of global CO 2 emissions [1]. On the other hand, ground granulated blast furnace slag (GGBFS), which is a byproduct of the steel industry, has been increasingly used in the concrete industry as a mineral admixture to partially replace cement.…”

“…On the other hand, ground granulated blast furnace slag (GGBFS), which is a byproduct of the steel industry, has been increasingly used in the concrete industry as a mineral admixture to partially replace cement. Slag blended concrete has many advantages, such as higher resistance against sulfate and seawater attack, higher late age strength, lower materials cost, and lower CO 2 emissions [1].…”

“…Carbonation can reduce the porosity of concrete and improve the compressive strength in the carbonated region of concrete. On the other hand, carbonation decreases the alkaline in concrete and induces the corrosion of steel rebar [1]. area of concrete are calculated.…”