Compressive stress–strain model for the estimation of the flexural capacity of reinforced geopolymer concrete members

Abstract

Global warming triggered efforts on sustainable materials in any area of production. Thus, the construction materials were also at the edge of a sharp change to achieve less harm to the environment by reducing the carbon print. Consequently, researchers have been trying to replace the cement from the mixtures of reinforced concrete as cement production causes large amounts of carbon dioxide emissions. Alkali‐activated binders are proved to be versatile alternatives to cementitious binders; however, accurate mathematical models to predict the capacities of these structural elements are limited in number. Therefore, in this study, a new stress–strain model has been developed to estimate the flexural capacity of geopolymer structural elements originated from construction and demolition waste. The study was initiated by formulating a novel stress–strain model applicable for defining the compressive behavior of geopolymer concrete. The formulation was based on recent experimental findings on flexural behavior of geopolymer beam specimens. Then, the performance of the proposed stress–strain model in estimating the ultimate moment capacities was investigated by using 36 bending tests from the literature. The results showed that the proposed model had very little deviations and enhanced accuracy compared with the literature available estimation method recommended by the ACI318. In addition, a soft database composed of 50 different beam specimens with varying mechanical properties and reinforcement patterns was formed. Numerical models corresponding to all possible combinations of each parameter were generated, and their load capacities were determined. After that, the estimation performances of the proposed method and the stress–strain models from the literature, and also the ACI318 procedure were examined. The conclusion of this check also yielded promising results with an absolute mean percentage error of 5.13% regardless of the mode of failures.

Investigating the Flexural Behavior of a Two-Span High-Performance Concrete Beam Using Experimentally Derived Stress Block Parameters

“…Designing HPC beams to withstand flexure can be a challenging task, as most standard codes and methods used for NSC cannot be applied to HSC. , To study the flexural behavior of higher-strength concretes, researchers have put forward stress block parameters and verified their experimental results, proposing substantial changes to current codes. − Stress block parameters have also been proposed for special types of concretes, such as geopolymer concrete (GPC). , However, it is unclear whether these parameters can be applied to HPC. While the ultimate strain of concrete recommended by the American code 441-R96 is 0.003, other codes such as EC-2, Canadian code, and IS Code limit it to 0.0035.…”

“… 7 − 14 Stress block parameters have also been proposed for special types of concretes, such as geopolymer concrete (GPC). 15 , 16 However, it is unclear whether these parameters can be applied to HPC. While the ultimate strain of concrete recommended by the American code 441-R96 17 is 0.003, other codes such as EC-2, 18 Canadian code, 19 and IS Code 20 limit it to 0.0035.…”

Mechanical properties and life cycle assessment of sugarcane bagasse and corn cob ashes‐based geopolymer concrete to promote circular economy

“…10 Another innovative solution to further mitigate CO 2 emissions amid an increase in concrete usage is to replace cement altogether with Alumino-Silicate (Al-Si) binders and develop a new type of concrete, that is, geopolymer concrete. [11][12][13][14] Geopolymers are inorganic polymers resulting from alkalination of an Al-Si-rich source material, forming tetrahedral polymeric structures. 15,16 The most common Al-Si source materials for geopolymer concrete synthesis are industrial wastes such as fly ash, silica fume, GGBFS etc.…”

“…WBCSD Cement Technology Roadmap found clinker reduction as the most economical solution, that is, blended cement with the utilization of a supplementary cementitious material (SCM) as a partial replacement of OPC 10 . Another innovative solution to further mitigate CO 2 emissions amid an increase in concrete usage is to replace cement altogether with Alumino‐Silicate (Al‐Si) binders and develop a new type of concrete, that is, geopolymer concrete 11–14 . Geopolymers are inorganic polymers resulting from alkalination of an Al‐Si‐rich source material, forming tetrahedral polymeric structures 15,16 …”