Self-compacting Geopolymer Concrete Research Articles

Probabilistic Estimation for Mechanical Properties of Self-Compacting Geopolymer Concrete Using Machine Learning Technique

Probabilistic Estimation for Mechanical Properties of Self-Compacting Geopolymer Concrete Using Machine Learning Technique

Engineering properties, sustainability performance and life cycle assessment of high strength self-compacting geopolymer concrete composites

The present investigation aims to study the mechanical and durability performances of Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBS), and Metakaolin (MK) blended Self-compacting Geopolymer concrete (SCGC). The significance of the investigation is to study the application of SCGC composites over conventional cement concrete for infrastructure. Furthermore, this investigation was focused on developing guidelines for SCGC. FA-SCGC (100% FA), FG-SCGC (50% FA + 50% GGBS), and FM-SCGC (50% FA + 50% MK) were exposed to acid and salt solutions. Two sets of curing conditions were adopted in the present investigation, namely, ambient and oven curing. In the case of ambient curing condition, the specimens are left at room temperature for a period of 28-days. Whereas, in the case of oven curing, after the rest period of 24 h, the specimens are cured in the oven at a temperature of 60 ℃ for a period of 24 h, then followed by ambient condition curing for the rest 27-days. Two types of acid solutions were employed: Sulfuric acid (H2SO4) and Nitric acid (HNO3) with a concentration of 2%. Two salt solutions are employed: magnesium sulfate (MgSO4) and sodium chloride (NaCl), with a 3.5% concentration. The parameters such as the physical observation, mass loss, and strength loss of SCGC composites exposed to acid and salt solutions were evaluated after 28-, 56-, 90-, 120-, 180-, 270- and 360-d of exposure. The result of all the three mixes, FA-SCGC, FG-SCGC, and FM-SCGC, show a better performance against acid and salt solutions. In addition, FG-SCGC is stronger and more durable than FM-SCGC, and FA-SCGC mixes; this could be attributed to the highly stable and cross-linked alumina-silica structure. The FA-SCGC shows better durability resistance but possesses lower mechanical properties among all the three mixes; this might be attributed to the low reactivity of FA particles, lower oxide composition of calcium, and more porous structure. It is found that amongst all the exposure conditions, exposing to H2SO4 environment causes severe damage to the concrete mixes. Further, a life-cycle assessment (LCA) examines the energy requirement and greenhouse gas emission (GHG-e) of normal strength and HSGC with various precursor materials. The FA-blended SCGC accounts for the least energy requirement for its production, while FG-SCGC possesses a slightly higher energy requirement than the FM-blended SCGC. The comparison of SCGC with the conventional Portland cement concrete shows that the FA-SCGC and FG-SCGC mixes have lower GHG-e by about 9.45 % and 5.88 %, respectively.

Mechanical Strength Estimation of Self-Compacting Geopolymer Concrete using ReLU based Deep Neural Network

ABSTRACT A deep learning artificial neural network model developed in Tensorflow using the ReLU function is presented in this paper to determine the effect of nine different input parameters on the mechanical strength of self-compacting geopolymer concrete (SGC). With the application of the above model, it has been observed that the convergence outcome of our model is predicted with minimum error. The novelty of our model is the ReLU function which improves the accuracy of the results. Our study presents a systematic investigation of the compressive strength, flexural strength, and tensile strengths of SGC depending upon nine vital parameters, such as GFS, Fly ash, NaOH, Na2SiO3 content, Age of specimens, Slump Value, T50, L Box and J Ring value as input. A large number of experiments were conducted to prepare a comprehensive database of the mechanical strength of Flyash-GFS-based SGC. The database has a total of 396 samples which were collected from 132 distinct mixtures, where the minimum and maximum compressive strength value is 7.7 Mpa and 66.7 Mpa, respectively. For the prediction based on deep learning, authors have performed an adequate number of iterations for both training and testing using error estimation parameters such as mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE). The error parameter values for the compressive strength of SGC are 2.42, 2.94 and 1.07, respectively, for MAE, RMSE and MSE. The other mechanical properties and their error parameter have also been thoroughly evaluated in our work.

Performance of Workability and Compressive Strength on Self-Compacting Geopolymer Concrete Based On High-Calcium Fly Ash With Addictive Admixture

Performance of Workability and Compressive Strength on Self-Compacting Geopolymer Concrete Based On High-Calcium Fly Ash With Addictive Admixture

Effect and influence of GGBS on properties of ambient cured self-compacting geopolymer concrete

The sustainable manufacture of self-compacting geopolymer concrete (SCGC), which has a lower carbon footprint compared with traditional concrete, reflects environmentally friendly concrete. In addition to the physical properties, this article presents an analysis of the fresh and mechanical properties of self-compacting geopolymer concrete. Some parameters such as varied sodium hydroxide molarity from 8 M to 16 M, sodium hydroxide/silicate solution ratio from 1:2.5 alkaline to GGBS, extra water ratio, GGBS content from 400 Kg/m3 to 500 Kg/m3. The current experimental evaluation examines the effectiveness of GGBS in improving SCGC workability and compressive strength due to durability. The sodium hydroxide molarity rises marginally reducing the fresh properties of self-compacting geopolymer concrete. As in the case of self-compacting concrete (SCC) with Portland cement, the durability properties of self-compacting geopolymer concrete are just a fraction of the compressive strength. The durability properties of self-compacting geopolymer concrete are adversely affected by rising test results of physical properties. Out of 5 different SCGC mix series, the optimum mix was achieved when a hundred percent Ground Granulated blast furnace slag (GGBS) and fifty percent river and M-sand were used, which not only showed better compressive strength and durability but also produced adequate workability within the EFNARC Self-Compacting Concrete (SCC) limits.

Influence of elevated temperature exposure on the interfacial shear strength capacity of binary blended high strength self-compacting geopolymer concrete

The development of sustainable infrastructure is a serious issue faced by modern society. Portland cement is one of the common ingredients in concrete, which influences construction activities. The major issue with the employment of cement in civil-based works is that it is responsible for carbon dioxide emission (CO2-e), the primary greenhouse gas responsible for global warming. Alternative to cement-based concrete, geopolymer concrete (GPC) employs zero cement for concrete production, leading to a reduction in CO2-e. In the case of mass concreting, interface/joints are developed, which are found to be the possible failure spots of brittle fracture. Concrete with different grades (strength) may interface, or other building materials, such as reinforcing materials. The interfacial bond strength has to be examined to ensure the homogeneity of the composite structures. The employment of shear ties at the interface ensures homogeneous behaviour. Moreover, a higher number of shear ties in the shear zone increases the cost of production. The interfacial shear strength (ISS) parameters will be miserably damaged in the concrete structures subjected to fire accidents, which might depend on the intensity of temperature exposure and its duration. The current study investigates the ISS of the High Strength Self-compacting geopolymer concrete (HSGC) in the interface of push-off samples. SCGC was made using binary blended composites, which comprised Fly Ash (FA), Metakaolin (MK), and Ground Granulated Blast Furnace Slag (GGBFS) as precursor materials. The work highlights the need to comprehend the reduction in shear strength of SCGC subjected to high temperatures. The fresh properties of the SCGC composites strictly adhered to the EFNARC guidelines. The SCGC composites, after their curing period, were exposed to 821 ℃, 925 ℃, 986 ℃, and 1029 ℃ following ISO 834 guidelines. Residual mechanical properties were examined after being cooled to room temperature.

A study on the effect of NaOH molarity on flyash based self compacting geopolymer concrete

The concrete industry has consistently pushed for sustainable development. This investigation aims to examine the characteristics of flyash-based self-compacting geopolymer concrete (SCGPC) made with varying NaOH molarities both while it is fresh and when it has hardened. The NaOH molarity is varied from 8 M to 16 M at an interval of 2 M. Sodium silicate (Na2SiO3) to sodium Hydroxide (NaOH) is kept at a constant ratio of 2. For the geopolymer process, the alkaline solution to Binder ratio (L/B) was kept at 0.45. Fresh properties like Slump flow, T50cm slump flow, L-Box and V-funnel have been done to assess the fresh properties of flyash based SCGPC confirming to EFNARC guidelines. Mechanical Strength properties such as Compressive, split-tensile, and flexural strength of the flyash based SCGPC were also determined at various ages. Prior to testing, all specimens are cured under ambient curing. Results indicate that the hardened properties of flyash based SCGPC are enhanced by the increase in molarity from 8 M to 16 M. Furthermore, as the molarity tends to rise, it is shown that the fresh properties slightly decrease.

Promulgation of engineering and sustainable performances of self-compacting geopolymer concrete

This study proposes a user- and eco-friendly methodology to optimize the mix proportion of superplasticizer-free self-compacting alkali-activated concrete (SCAAC). This methodology allows tailoring SCAAC for a desired water-binder ratio, alkaline activator content, and ratio to realize a targeted compressive strength and sustainability index. The validity of the proposed methodology was established via a series of physical tests and ANOVA analyses. The findings indicate that the attained flow properties of the developed SCAAC have significantly improved, i.e., from 490 to 705 mm for mixes of water/binder ratio of 0.45–0.65. The compressive strength results indicates that the water/binder ratio of 0.45 possess 46 MPa at the curing age of 28-d, whereas the water/binder ratio of 0.65 possess a 28-d strength of 39 MPa. The present work proposes the guidelines for the production of SCAAC, since there is no guidelines or standards for SCAAC. To showcase the proposed methodology, this study concludes with a step-by-step procedure for arriving at an optimized design mix for a superplasticizer-free Fly Ash Ground Granulated Blast Furnace Slag (FA-GGBS) based SCAAC. Furthermore, sustainability index (Cost, Carbon and Energy efficiency) analysis was performed for the SCAAC mixes with and without SP. From the analysis it is found that an increase in the SP dosage from 1 to 6% increases the cost of the production of the mix. Also, it increases the energy demand for its production and liberates huge amount of carbon dioxide in the open atmosphere.

Advancements in self-compacting geopolymer concrete: A comprehensive overview

The present generationof concrete, known as geopolymer concrete (GPC), is created through the polymerization of aluminosilicate minerals with an alkali-activated solution (AAS). The normal hydration process has no bearing on GPC development. It defends the atmosphere from CO2 emissions caused by cement-making procedures. Making GPC self-compacting, also known as self-compacting Geopolymer concrete, allows for the avoidance of the dynamic compaction needed for the compaction process of GPC. The effect of numerous factors, including fibers, molarity, binding materials, and superplasticizer on the mechanical characteristics and workability of SCGC, as well as any gaps and potential future applications, are critically reviewed in this research. In addition to having fewer negative effects on the environment, SCGC also better utilizes waste and conserves resources than ordinary concrete, according to the research currently available. Despite its enormous potential, the lack of knowledge about the different factors that influence SCGC creation is the cause of its limited utilization. The current publication focuses on the characteristics of SCGC that make it widely accepted, as well as the variables influencing SCGC creation.

Identification of Sustainability factors of Self-Compacting Geopolymer Concrete for precast construction using SEM

Today's cement concrete industry is a major polluter. Cement, used as a binder in cement concrete, is made by high-temperature combustion, which raises atmospheric CO2 levels and contributes to climate change and natural resource depletion. As raw supplies diminish, several governments begin to levy carbon taxes. Numerous research have been undertaken to produce an innovative and ecologically advantageous construction material known as Geopolymer concrete (GC) in order to minimise and eliminate greenhouse gas emissions. In order to connect coarse aggregates (CA), fine aggregates (FA), and other materials in GC and improve concrete quality while using fewer natural resources, it is essential to replace cement with a byproduct substance rich in silicon and aluminium, such as red mud, fly ash (FA), rice husk ash (RHA), silica fume (SF), ground granulated blast furnace slag (GGBS), and others, activated by a high alkaline solution (AS). In this study were surveyed online and precast self-compacting geopolymer concrete's sustainability was examined. The data underwent factor analysis. Principal component analysis is used to extract factors. According to the research, there are 9 key variables to consider: Reduction in Carbon Footprint, Utilization of Waste Materials, Environmentally Friendly, Reduce Water usage during production, Low Maintenance, Augmentation of Mechanical Properties of Concrete, Natural Materials, Cost Effective, Reduction in Energy consumption during production. These are the nine primary sustainability criteria of Self-Compacting Geopolymer Concrete for Precast Construction.

Evaluating the impact of nano-silica on characteristics of self-compacting geopolymer concrete with waste tire steel fiber

Evaluating the impact of nano-silica on characteristics of self-compacting geopolymer concrete with waste tire steel fiber

The effect of materials and curing system on the behavior of self-compacting geopolymer concrete

Abstract The aim of the present work was to investigate and achieve the optimum compressive strength of self-compacting geopolymer concrete (SCGC). Fly ash (FA) and ground granulated blast furnace slag (GGBFS) are used at different ratios as binder materials to produce the SCGC mixes. Alkaline solution was a mix of sodium silicate and sodium hydroxide. Three different ratios of binder materials were used to produce SCGC (0FA-100GGBFS; 50FA-50GGBFS; and 100FA-0GGBFS). The total binder weight was 500 kg/m3 within a constant alkali–binder proportion (0.5). Two curing conditions were used, at ambient environment and heat curing at 110°C for 24 h. The compressive strength and fresh properties of SCGC are evaluated. The compressive strength is utilized to demonstrate the mechanical properties of SCGC. The compressive strength is investigated at two ages (7 and 28 days). The results showed that the use of GGBFS had a negative effect on the fresh properties of SCGC. However, it has a significant impact on the mechanical behavior of the SCGC. SCGC’s early strength is heavily involved in heat curing. The compressive strength of 100% GGBFS in the ambient environment after 28 days was more than that of GGBFS cured at 110°C. The optimum eco-friendly mix is 50FA-50GGBFS.

Characterisation of eco-friendly self-compacting geopolymer concrete for fire endurance properties

Characterisation of eco-friendly self-compacting geopolymer concrete for fire endurance properties

Experimental and Artificial Neural Network-Based Study on the Sorptivity Characteristics of Geopolymer Concrete with Recycled Cementitious Materials and Basalt Fibres

The environmental concerns regarding the production of the most widely consumed cement construction material have led to the need for developing sustainable alternatives. Using recycled industry waste products such as fly ash and slag via geopolymerisation has led to the development of geopolymer cement—an efficient replacement for ordinary Portland cement (OPC). Adopting geopolymer cement and concrete as a construction material reduces greenhouse gas and promotes the recycling of waste products. This study explores the suitability of a unique geopolymer concrete mix made of recycled cementitious materials including industry waste products such as fly ash, micro fly ash and slag for use in aggressive environments. Sorptivity tests are conducted to assess the durability of concrete and indicate the cementitious material’s ability to transmit water through the capillary forces. This study thus reports on the sorptivity characteristics of a newly developed self-compacting geopolymer concrete and two other fibre geopolymer concrete mixes containing 1% (by weight) of 12 mm- or 30 mm-long basalt fibres. The addition of basalt fibres indicated less water absorption and moisture ingress than the mix without fibres. The study used 18 specimens from three geopolymer concrete mixes, and the results showed that adding fibres improved the durability performance in terms of resistance to moisture ingress. Finally, an artificial neural network model is developed to predict the absorption rates of geopolymer concrete specimens using MATLAB. The prediction models reported excellent agreement between experimental and simulated datasets.

Fresh, Mechanical, and Durability Behavior of Fly Ash-Based Self Compacted Geopolymer Concrete: Effect of Slag Content and Various Curing Conditions.

This investigation evaluates the influence of various curing conditions and slag inclusion on the fresh, mechanical, and durability properties of self-compacting geopolymer concrete (SCGC) based on fly ash (FA). Curing temperature and curing time have a vital role in the strength and microstructure of geopolymer concrete. Therefore, to begin the research, the impacts of different curing conditions (curing temperature and curing time) and slag content on the compressive strength of FA-based SCGC were examined to determine the optimum curing method. A series of four SCGC mixes with a fixed binder content (450 kg/m3) and an alkaline/binder ratio of 0.5 was designated to conduct a parametric study. FA was replaced with slag at four different substitution percentages, including 0%, 30%, 50%, and 100% of the total weight of the binder. The fresh properties of the produced SCGC specimens were investigated in terms of slump flow diameter, T50 flow time, and L-box height ratio. Additionally, the following mechanical properties of SCGC specimens were investigated: modulus of elasticity and fracture parameters. The water permeability and freezing–thawing resistance were studied to determine the durability behavior of SCGC. In this study, the optimum curing temperature was 85 °C for the duration of 24 h, which provided the maximum compressive strength. The results confirmed that adding slag affected the workability of SCGC mixtures. However, the mechanical characteristics, fracture parameters, and durability performance of SCGC were improved for slag-rich mixtures. When using 50% slag instead of FA, the percentage increase in compressive, flexural, elastic module, and fracture energy test values were about 100%, 43%, 58%, and 55%, respectively, whilst the percentage decrease in water permeability was 65% and the resistance to freeze–thaw test in terms of surface scaling was enhanced by 79%.

Strength, durability, and microstructure of self-compacting geopolymer concrete produced with copper slag aggregates.

Lack of vibrations on fresh concrete negatively influences the compaction and thus the quality of concrete. This is particularly concerning with geopolymer concrete (GPC) containing sodium silicate (Na2SiO3), which is viscous in nature. In this study, self-compacting geopolymer concrete (SCGC) containing fly ash (FA) and ultrafine slag (UFS) with copper slag aggregates (CSA) was proposed and investigated. CSA were used as a substitute to sand (by weight) in SCGC at different percentages up to 60%. In the fresh state, slump, T500 slump flow, V-funnel, L-box, U-box, and sieve aggregation ratio tests were performed to investigate flowability, passing ability, and viscosity. At the hardened state, the compressive strength, water absorption, chloride ion resistance and sorptivity tests were examined. The flowability of SCGC improved when CSA were added, and the highest slump of 735mm was achieved for the mix with 60% CSA. Substitution of up to 20% of CSA enhanced the properties of SCGC at all ages. Mix having 20% CSA (20CSA-SCGC) was superior to other mixes, exhibiting the highest compressive strength (47MPa) at 365days while possessing the lowest water absorption, sorptivity, and the highest chloride ion resistance. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analyses also confirmed the improved microstructure of Mix 20CSA-SCGC. Meanwhile, X-ray diffraction (XRD) analysis confirmed the presence of quartz and calcium silicate hydrate (CSH) products, which were the main contributors to properties enhancement.

Self-compacting geopolymer concrete

Self-compacting geopolymer concrete (SCGC) is a novel material. and a modern high-performance concrete that doesn’t require Ordinary Portland cement and additional compaction. SCGC is made up of industrial byproducts, with high Alumina and Silica composition, and uses super plasticizer as a binder for matrix formation and strength. This research examines SCGC, which is prepared with various percentages of Ground Granulated Blast Furnace Slag (GGBFS), Silica Fume (SF) and Metakaolin (MK), activated with various molarities of alkaline solution containing sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Fresh and hardened characteristics along with microstructural studies are discussed. The beams are analysed using ANSYS software.

Structural Performance of Modular Sandwich Composite Floor Slabs Containing Basalt FRP-Reinforced Self-Compacting Geopolymer Concrete

A newly developed innovative steel–geopolymer concrete composite floor slab for use in modular construction is investigated in this study. We present experimental results on the flexural behaviour of eight modular sandwich composite floor slabs with different configurations containing self-compacting geopolymer concrete (SCGC) as infill and Basalt FRP (BFRP) bars as reinforcement. The use of sustainable infill material such as SCGC and non-corrosive BFRP in the proposed composite floor slabs is beneficial from the perspective of environmental sustainability. This study also compares the performance of these composite floor slabs against their hollow counterparts. The overlap between the cells in multi-cell panels acts as additional partitioning walls. The infill material offers the sandwich composite floor slabs significant advantages by improving their load-carrying capacity. A critical analysis of the composite floor slabs for load displacement, failure modes, and strain behaviour is also conducted. The study concludes that the sandwich panels with multiple smaller cells and infill materials exhibit a sound structural performance, reporting a 6–8 times higher load-carrying capacity than their hollow counterparts. A comparison of hollow and infilled panels shows that the infill sandwich panels are suitable as structural slabs. At the same time, the former is more suitable for temporary formworks, shelter, and pedestrian platform applications.

Marine Geopolymer Concrete—A Hybrid Curable Self-Compacting Sustainable Concrete for Marine Applications

Marine environments are widely addressed as a serious threat to coastal concrete structures due to higher repair and rehabilitation costs. The rising concerns of climate change and related issues also require marine structures to be resilient and sustainable at the same time. Geopolymer concrete has been given more significant consideration as an alternative, reporting better resistance to harsh and hazardous environmental exposure, including sulphate attacks, chloride attacks, and freeze–thaw climates. This study investigated the mechanical properties of fly ash (FA) and ground granulated blast furnace slag (GGBFS)-based self-compacting geopolymer concrete (SCGC), subjected to short term ambient and marine curing conditions. The mechanical performance, inclusive of compressive strength, tensile strength, and modulus of elasticity under three-month marine exposure compared to an ambient environment, indicates that the SCGC mix offered an increase in strength. It is reported that the compressive strength of SCGC increased to the range of 50 MPa after marine exposure in comparison to the 40 MPa strength after 28-day curing. A similar increase in indirect tensile strength and modulus of elasticity were observed for the test specimens, with no signs of leaching of salts under marine exposure. Thus, the current SCGC acts as a sustainable construction material in counteracting the threats of marine degradation in civil structural components.

Shear-bond behavior of self-compacting geopolymer concrete to conventional concrete

The shear-bond behavior of two mechanically different concretes is fundamental when conducting external reinforcement, retrofitting, or repair. The two components are designed to possess full strain compatibility in sustaining the stress transfer between the two parts throughout the loading sequence. This work investigated the shear-bond behavior between conventional and self-compacting geopolymer concrete based on the push-off method. The influence of surface roughness on the bond behavior was studied, and a finite element model was constructed and validated to the experimental data. Surprisingly, the chemical bond characteristics of geopolymer concrete have little effect on the bond strength as compared to conventional concrete having the same compression strengths, but significantly influences the load-slip pattern of the interface. As expected, the bond strength was positively influenced by the interface roughness. All failure modes were unmistakably brittle. The strain deformation pattern generated from the finite element model underlined that large strains and stresses were present at the far ends in the interface, where initial cracking was detected in these regions. The study concluded that self-compacting geopolymer concrete is a perfect solution for older structure’s external strengthening or retrofitting. This material has a better sustainable and a more environmentally friendly character.