scholarly journals Engineering Properties of Waste Sawdust-Based Lightweight Alkali-Activated Concrete: Experimental Assessment and Numerical Prediction

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5490
Author(s):  
Hisham Alabduljabbar ◽  
Ghasan Fahim Huseien ◽  
Abdul Rahman Mohd Sam ◽  
Rayed Alyouef ◽  
Hassan Amer Algaifi ◽  
...  
Keyword(s):  
High Performance ◽  
Lightweight Concrete ◽  
Energy Utilization ◽  
Engineering Properties ◽  
Conventional Concrete ◽  
Volume Percentage ◽  
Granulated Blast Furnace Slag ◽  
Low Sodium ◽  
Artificial Neural Network Ann ◽  
Alkali Activated

Alkali activated concretes have emerged as a prospective alternative to conventional concrete wherein diverse waste materials have been converted as valuable spin-offs. This paper presents a wide experimental study on the sustainability of employing waste sawdust as a fine/coarse aggregate replacement incorporating fly ash (FA) and granulated blast furnace slag (GBFS) to make high-performance cement-free lightweight concretes. Waste sawdust was replaced with aggregate at 0, 25, 50, 75, and 100 vol% incorporating alkali binder, including 70% FA and 30% GBFS. The blend was activated using a low sodium hydroxide concentration (2 M). The acoustic, thermal, and predicted engineering properties of concretes were evaluated, and the life cycle of various mixtures were calculated to investigate the sustainability of concrete. Besides this, by using the available experimental test database, an optimized Artificial Neural Network (ANN) was developed to estimate the mechanical properties of the designed alkali-activated mortar mixes depending on each sawdust volume percentage. Based on the findings, it was found that the sound absorption and reduction in thermal conductivity were enhanced with increasing sawdust contents. The compressive strengths of the specimens were found to be influenced by the sawdust content and the strength dropped from 65 to 48 MPa with the corresponding increase in the sawdust levels from 0% up to 100%. The results also showed that the emissions of carbon dioxide, energy utilization, and outlay tended to drop with an increase in the amount of sawdust and show more the lightweight concrete to be more sustainable for construction applications.

scholarly journals Suitability of Scoria as Fine Aggregate and Its Effect on the Properties of Concrete

2019 ◽  
Vol 11 (17) ◽  
pp. 4647 ◽  
Author(s):  
Warati ◽  
Darwish ◽  
Feyessa ◽  
Ghebrab
Keyword(s):  
Construction Materials ◽  
Energy Utilization ◽  
Engineering Properties ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Test Results ◽  
River Sand ◽  
Conventional Concrete ◽  
Efficient Energy ◽  
Concrete Production

The increase in the demand for concrete production for the development of infrastructures in developing countries like Ethiopia leads to the depletion of virgin aggregates and high cement demand, which imposes negative environmental impacts. In sustainable development, there is a need for construction materials to focus on the economy, efficient energy utilization, and environmental protections. One of the strategies in green concrete production is the use of locally available construction materials. Scoria is widely available around the central towns of Ethiopia, especially around the rift valley regions where huge construction activities are taking place. The aim of this paper is therefore to analyze the suitability of scoria as a fine aggregate for concrete production and its effect on the properties of concrete. A differing ratio of scoria was considered as a partial replacement of fine aggregate with river sand after analyzing its engineering properties, and its effect on the mechanical properties of concrete were examined. The test results on the engineering properties of scoria revealed that the material is suitable to be used as a fine aggregate in concrete production. The replacement of scoria with river sand also enhanced the mechanical strength of the concrete. Generally, the findings of the experimental study showed that scoria could replace river sand by up to 50% for conventional concrete production.

Engineering Properties of High-Performance Alkali-Activated Mortars

2021 ◽  
pp. 49-71
Author(s):  
Ghasan Fahim Huseien ◽  
Nur Hafizah A. Khalid ◽  
Jahangir Mirza
Keyword(s):  
High Performance ◽  
Engineering Properties ◽  
Alkali Activated

scholarly journals Setting, Strength, and Autogenous Shrinkage of Alkali-Activated Fly Ash and Slag Pastes: Effect of Slag Content

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2121 ◽  
Author(s):  
Marija Nedeljković ◽  
Zhenming Li ◽  
Guang Ye
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Experimental Studies ◽  
Autogenous Shrinkage ◽  
Engineering Properties ◽  
Engineering Practice ◽  
Granulated Blast Furnace Slag ◽  
Alkali Activated

The engineering properties of alkali activated materials (AAMs) mainly depend on the constituent materials and their mixture proportions. Despite many studies on the characterization of AAMs, guidelines for mixture design of AAMs and their applications in engineering practice are not available. Extensive experimental studies are still necessary for the investigation of the role of different constituents on the properties of AAMs. This paper focuses on the development of alkali-activated fly ash (FA) and ground granulated blast furnace slag (GBFS) paste mixtures in order to determine their suitability for making concretes. In particular, the influence of the GBFS/FA ratio and liquid-to-binder (l/b) ratio on the slump, setting, strength, and autogenous shrinkage of the alkali activated pastes is studied.It is shown that fresh properties largely depend on the type of precursor (GBFS or FA). The slump and setting time of GBFS-rich pastes was significantly reduced. These pastes also have higher compressive strength than FA-rich pastes. The study identifies important practical challenges for application of the studied mixtures, such as the behavior of their flexural strength and high amplitudes of autogenous shrinkage of GBFS-rich mixtures. Finally, the optimum GBFS/FA ratio for their future use in concretes is recommended.

Predicting Compressive Strength of Sustainable Self-Consolidating Concrete Using Random Forest

2017 ◽  
Vol 744 ◽  
pp. 141-145 ◽  
Author(s):  
Osama Ahmed Mohamed ◽  
Modafar Ati ◽  
Omar Fawwaz Najm
Keyword(s):  
Compressive Strength ◽  
Random Forest ◽  
Engineering Properties ◽  
Conventional Concrete ◽  
Self Consolidating Concrete ◽  
Granulated Blast Furnace Slag ◽  
High Level ◽  
Furnace Slag ◽  
Production Industry

This paper demonstrates the application of Random Forest (RF) algorithm for prediction of compressive strength of sustainable self-consolidating concrete (SCC) in which significant amount of cement was replaced with minerals such as fly ash, ground granulated blast furnace slag (GGBS), and silica fume. SCC improves the quality of the finished concrete product and is considered an environmentally friendly alternative to conventional concrete. RF proved capable of predicting compressive strength with high accuracy. The ability of RF algorithm to predict compressive strength established confidence on the experimental data itself which can be used for further studies on properties of self-consolidating concrete. The high level of accuracy in predicting essential engineering properties of concrete through RF algorithms offers important opportunities to enhance quality in ready mix production industry.

scholarly journals Machine Learning Approaches for Prediction of the Compressive Strength of Alkali Activated Termite Mound Soil

2021 ◽  
Vol 11 (11) ◽  
pp. 4754
Author(s):  
Assia Aboubakar Mahamat ◽  
Moussa Mahamat Boukar ◽  
Nurudeen Mahmud Ibrahim ◽  
Tido Tiwa Stanislas ◽  
Numfor Linda Bih ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Materials ◽  
Curing Temperature ◽  
Sustainable Construction ◽  
Support Vector ◽  
Learning Approaches ◽  
Artificial Neural Network Ann ◽  
Curing Regime ◽  
Alkali Activated

Earth-based materials have shown promise in the development of ecofriendly and sustainable construction materials. However, their unconventional usage in the construction field makes the estimation of their properties difficult and inaccurate. Often, the determination of their properties is conducted based on a conventional materials procedure. Hence, there is inaccuracy in understanding the properties of the unconventional materials. To obtain more accurate properties, a support vector machine (SVM), artificial neural network (ANN) and linear regression (LR) were used to predict the compressive strength of the alkali-activated termite soil. In this study, factors such as activator concentration, Si/Al, initial curing temperature, water absorption, weight and curing regime were used as input parameters due to their significant effect in the compressive strength. The experimental results depict that SVM outperforms ANN and LR in terms of R2 score and root mean square error (RMSE).

scholarly journals Synthesis of Ambient Cured GGBFS Based Alkali Activated Binder Using a Sole Alkaline Activator: A Feasibility Study

2021 ◽  
Vol 11 (13) ◽  
pp. 5887
Author(s):  
Thandiwe Sithole ◽  
Nelson Tsotetsi ◽  
Tebogo Mashifana
Keyword(s):  
Silicate Solution ◽  
Environmental Footprint ◽  
Ambient Temperatures ◽  
Granulated Blast Furnace Slag ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Porous Morphology ◽  
Furnace Slag ◽  
Alkali Activated

Utilisation of industrial waste-based material to develop a novel binding material as an alternative to Ordinary Portland Cement (OPC) has attracted growing attention recently to reduce or eliminate the environmental footprint associated with OPC. This paper presents an experimental study on the synthesis and evaluation of alkali activated Ground granulated blast furnace slag (GGBFS) composite using a NaOH solution as an alkaline activator without addition of silicate solution. Different NaOH concentrations were used to produce varied GGBFS based alkali activated composites that were evaluated for Uncofined Compressive Strength (UCS), durability, leachability, and microstructural performance. Alkali activated GGBFS composite prepared with 15 M NaOH solution at 15% L/S ratio achieved a UCS of 61.43 MPa cured for 90 days at ambient temperatures. The microstructural results revealed the formation of zeolites, with dense and non-porous morphology. Alkali activated GGBFS based composites can be synthesized using a sole alkaline activator with potential to reduce CO2 emission. The metal leaching tests revealed that there are no potential environmental pollution threats posed by the synthesized alkali activated GGBFS composites for long-term use.

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