Workability, microstructure, strength properties and durability properties of graphene oxide reinforced cement paste

Synthesis, characterization, and application of graphene oxide and reduced graphene oxide and its influence on rheology, microstructure, and mechanical strength of cement paste

Graphene oxide (GO) has attracted significant attention as a nano-reinforcement for cement-based materials, owing to its exceptional mechanical properties and abundant surface functional groups. However, the precise mechanisms governing its effects in cement composites remain inadequately understood due to inconsistencies and gaps in the existing literature. This review conducts a comprehensive analysis of the dispersion and reinforcement effects of GO in cement materials, focusing on three key areas: (1) challenges associated with achieving uniform dispersion of GO in the high-pH environment of cement slurries and potential strategies to address them; (2) the influence of GO on the macroscopic properties of cementitious composites, including workability, load-bearing capacity, flexural strength, fracture resistance, and durability; and (3) the reinforcement mechanisms of GO, encompassing its role in hydration kinetics, alterations to the calcium-silicate-hydrate (C-S-H) structure, and bonding interactions at the cement matrix interface. Furthermore, recent advancements in optimizing the dispersion and reinforcement effects of GO, such as surface modification techniques, are explored, emphasizing its potential for multifunctional and intelligent applications. This review aims to provide engineering professionals with the latest insights into the application of graphene oxide as a nano-reinforcement in cement-based composites, while offering valuable guidance and direction for future research in this field.

In previous work focused on using recycled concrete powder as cement replacement the basic dependency of the mechanical properties on the amount of recycled concrete powder was defined. Influence of the amount of recycled concrete powder on the flexural and compressive strength was shown on 0, 33, 67 and 100 wt. % cement replacement. Based on the previous data the strength properties of the cement paste with recycled concrete powder below 33 wt. % was almost constant and strength properties were comparable with reference sample made of cement only. After the recycled concrete powder in cement paste exceeded amount of 33 wt. % the flexural and compressive strength decrease rapidly. In case of 67 wt. % amount of recycled concrete powder the compressive strength decrease about 65 %. The aim of this article is define critical amount of recycled concrete powder in cement paste when strength properties start decrease rapidly and cement replacement is no longer beneficial. This critical amount will be located somewhere between 30 and 50 wt. % of recycled concrete powder. Replacement below critical amount could lead to cost reduction of cement composites and also the negative impact of the cement production and concrete disposal on environmental could be reduced.

In recent years, nano-sized graphene oxide (GO) has come to the fore as a promising material for enhancing the mechanical and durability performance of cementitious composites. On the other hand, partial substitution of industrial wastes and by-products into cementitious composites attracts the attention of researchers in order to ensure long-term sustainability. In order to combine these two aspects, the main focus of this study is to examine the effect of 0.05% and 0.1% GO-reinforcement on the slump, 7 and 28-day compressive and flexural strength and 28-day rapid chloride permeability test (RCPT) properties of cementitious composites. In this context, mixtures with three different binder combinations, a control, a silica fume (SF) substitution, and a fly ash (FA) substitution, were designed. The results showed that GO-reinforcement reduced the slump values of the mixtures between 5-15 mm, while the 28-day compressive strengths increased in the range of 9.82%-13.61% with 0.05% GO-reinforcement, and in the range of 17.02%-20.68% with 0.1% GO-reinforcement. The 28-day flexural strength of the mixtures increased by about 10% on average as a result of 0.1% GO-reinforcement. According to the RCPT anaylses, it was observed that the chloride permeability of the mixtures decreased up to 18.85% with 0.1% GO-reinforcement.

A research has been done on the mechanical bricking test with the addition of bagasse ash. In this study, the tested bricks tested were compressive and flexural strength. The purpose of this study was to determine the effect of adding bagasse ash to the mechanical properties of the concrete brick. The percentage variation of bagasse ash, cement, and sand are 0%:30%:70%, 5%:25%:70%, 10%:20%:70%, 15%:15%:70%, 20%:10%:70% with Water Cement Ratio of 0.5 in all variations. The addition of bagasse ash as a substitute for cement significantly affected the characteristics of the concrete brick. With the addition of bagasse ash in a mixture of 5-20% causes the compressive strength to decrease. While the flexural strength has increased in the variation of the mixture of 5-10% and has decreased in the variation of the mixture of 15-20%. The most optimal composition of mixing bagasse ash, cement, and sand is at 5% mixture variation for compressive strength and flexural strength testing because it meets SNI 03-0348-1989 standards. Whereas the other mixed variations are not optimal. Keyword s : Bagasse ash, Compressive Strength, and Flexural Strength .

Nowadays, there is paying an attention to the utilization of natural, renewable and biodegradable resources of raw materials of lignocellulosic character, residues from agricultural crops and wood processing as well as waste from papermaking industry in building composite materials preparing. Also recycled fibres coming from waste paper are considered as valuable material. The objective of this study is to utilize these recycled cellulosic fibres into cement composites and characterise their impact on resulting physical and mechanical properties of fresh and hardened cement composites. Manufactured cement composites contained 0.2%, 0.3% and 0.5% addition of cellulosic fibres. In fresh fibre cement mixtures reduction in workability with increasing amount of cellulose fibres was noticed. Density as well as compressive and flexural strength of 28 and 90 days hardened fibre cement composites was tested. Distribution of cellulosic fibres with 0.5% addition in hardened fibre cement composites was also observed. The results of density determination of 28 and 90 days hardened fibre cement composites showed reduction in their values related to weight lighter concretes. Compressive strengths of fibre cement composites have shown decreasing character with increasing added amount of cellulosic fibres into the mixture up to 0.5%. Maximal decrease in compressive strength values was observed in composites containing 0.5% of cellulosic fibres. However, obtained strength parameter values of hardened composites had satisfying results for their application in construction as non-load bearing building material.

Strength attributes and microstructural characterization of basalt fibre incorporated self-compacting concrete

Biochar is an industrial byproduct that, after thermal treatment through pyrolysis, results in a material primarily composed of solid carbon. It has potential for use as a chemical regulator and as a carbon uptake to reduce emissions in cementitious composites. It presents itself as a potential alternative for reducing the carbon footprint of the cement industry. In this manuscript was evaluated the performance of biochar in cementitious composites in partial substitution cement Portland in levels of 1, 2 and 3% in weight. For this, cement pastes with a water/cement ratio of 0.5 were produced and tested fresh and hardened state. Specific gravity, trapped air, mini-slump and hydration kinetics (evaluated by isothermal calorimetry up to 48h) of the pastes were determined in the fresh state. Thus, in the hardened state, the compressive and flexural strength tests at 28 days, specific gravity, void ratio, MEV, DRX, FTIR and TG were carried out. In the fresh state, the sample with 3% biochar showed 13.03% higher workability and an increase of up to 77.9% in the induction period compared to the reference series. In the hardened state, the sample with 2% biochar achieved a 215.1% higher rate of entrapped air compared to the reference series. Regarding carbon uptake, the biochar samples showed an average of 9.77% more uptake than the reference series, while the 1% biochar series showed 11.01% more uptake than the reference series. This simple methodology, replacing cement with biochar, highlights the potential of using biochar to promote a cement industry with a lower carbon footprint. It employs a simple methodology that does not require significant industrial changes to the current production line of the construction industry, proving itself as an alternative for short-term industrial application. • 1% biochar resulted in a 34.4% increase in flexural strength. • Among the samples with biochar, there was a 9.77% increase in CO 2 absorption. • 1% biochar resulted in a 31.3% increase in CO 2 absorption.

Concrete made from ordinary Portland cement is one of the most widely used construction materials due to its excellent compressive strength. However, concrete lacks ductility resulting in low tensile strength and flexural strength, and poor resistance to crack formation. Studies have demonstrated that the addition of graphene oxide (GO) nanosheet can effectively enhance the compressive and flexural properties of ordinary Portland cement paste, confirming GO nanosheet as an excellent candidate for using as nano-reinforcement in cement-based composites. To date, the majority of studies have focused on cement pastes and mortars. Only limited investigations into concretes incorporating GO nanosheets have been reported. This paper presents an experimental investigation on the slump and physical properties of concrete reinforced with GO nanosheets at additions from 0.00% to 0.08% by weight of cement and a water–cement ratio of 0.5. The study demonstrates that the addition of GO nanosheets improves the compressive strength, flexural strength, and split tensile strength of concrete, whereas the slump of concrete decreases with increasing GO nanosheet content. The results also demonstrate that 0.03% by weight of cement is the optimum value of GO nanosheet dosage for improving the split tensile strength of concrete.

The influence of graphene oxide (GO) and polyvinyl alcohol (PVA) fiber on the mechanical performance, durability, and microstructure of cement-based materials was investigated in this study. The results revealed that compared with a control sample, the mechanical strength and durability of cement-based materials were significantly improved by adding PVA fiber and GO. The compressive and flexural strength at 28 d were increased by 30.2% and 39.3%, respectively. The chloride migration coefficient at 28 d was reduced from 7.3 × 10−12 m2/s to 4.3 × 10−12 m2/s. Under a sulfate corrosion condition for 135 d, the compressive and flexural strength still showed a 13.9% and 12.3% gain, respectively. Furthermore, from the Mercury Intrusion Porosimetry (MIP) test, with the incorporation of GO, the cumulative porosity decreased from more than 0.13 cm3/g to about 0.03 cm3/g, and the proportion of large capillary pores reduced from around 80% to 30% and that of medium capillary pores increased from approximately 20% to 50%. Scanning electron microscope (SEM) images showed a significant amount of hydration products adhering to the surface of PVA fiber in the GO and PVA fiber modified sample. The addition of GO coupling with PVA fiber in cement-based materials could promote hydration of cement, refine the microstructure, and significantly improve mechanical strength and durability.

Prediction of the strength properties of roller compacted concrete from mathematical models is significant for rapid decision of the quality of the pavement. In the present assessment, roller compacted concrete slab samples have been prepared in the laboratory using 12 percentage of Portland cement by weight of aggregates. Cube, core, and beam specimens were extracted from the slab samples and tested for compressive, indirect tensile, and flexural strength at the age of 28 days. Strength test results were corelated among each other and mathematical models were obtained. It was observed that low significance of aggregates gradation type on the compressive and tensile strength exists. However, high influence of dense gradation on flexural strength could be detected. The flexural strength of dense graded mixture is higher than that of gap graded mixtures. The compressive strength of gap graded mixture is higher than that of dense graded mixture. It can be concluded that the flexural strength is higher than the tensile strength by (2.17 and 1.24) folds for dense and gap graded mixtures respectively. The compressive strength is higher than tensile strength by (5.72 and 4.87) folds for dense and gap graded mixtures respectively. The compressive strength is higher than the flexural strength by (3.4 and 2.49) folds for dense and gap graded roller compacted concrete respectively. The obtained mathematical models exhibit high coefficient of determination and may be implemented in verification of the specific strength property based on other measured strength properties of roller compacted concrete.

The aim of this work was to produce highly active and amorphous nano sized pozzolana by means of thermal activation of nanoclays and to utilize the thermally activated nanoclays as additives in white Portland cement pastes (WPC) to improve their thermo mechanical properties. The nanoclay used in this investigation is kaolin clay. The nano Kaolin was thermally treated at 750°C for 2 h to obtain active amorphous nano metakaolin (NMK). The effect of thermal activation on the dehydroxylation of the kaolin and the surface morphology of the resulting amorphous NMK were determined by using different techniques: X-ray diffraction spectroscopy (XRD), differential thermal analysis (DTA) and Transmission electron microscopy (TEM). NMK were incorporated at a rate of 2, 4, 6, 8, 10, 12, and 14% by weight of cement. Hardened blended cement pastes were prepared by using water/cement ratio (W/C) of 0.3 by weight and hydrated for various curing ages 3, 7, and 28 days. In order to study the mechanical and physical characteristics of the hardened cement pastes incorporating NMK, different techniques were used such as compressive and flexure strength testing, differential scanning calorimeter (DSC), x-ray diffraction (XRD), and scanning electron microscope (SEM). The experimental results of this study showed that thermal activation of the nano kaolin leads to transformation of the kaolinite to amorphous phase accompanied with the reduction in grain size. The partial replacement of cement by NMK is helpful in enhancing the compressive and flexure strength of cement products. There was an enhancement of compressive strength by about 50% and flexure strength by 36% at 10% nanoclay. The microstructure of the cement blended with NMK was denser, compact, and more uniform than that of the conventional cement microstructure.

This experimental inquiry delves into the evaluation of compressive and flexural strengths in concrete through the utilization of waste glass powder as a partial substitute for cement. Compressive strength is a key metric, indicating the concrete’s ability to effectively support structural axial loads, while flexural strength signifies its capacity to withstand deformation under bending, specifically the maximum tensile stress it can endure without fracturing when subjected to a bending moment. Certain pozzolanic materials have demonstrated the ability to enhance the mechanical strength of concrete when used as a cement replacement, and waste glass powder is among them. To address this, the experimental investigation included the substitution of cement with glass powder at different proportions (0%, 10%, 15%, 17.5%, and 20%) in both cubic and prismatic samples. Compressive strength and flexural strength tests were made following the curing of the samples for 7, 14, and 28 days. The findings indicated that the 17.5% cement replacement level exhibited a 6.07% over-strength for compressive strength and a 6.85% over-strength for flexural strength on the 28th day. However, the 15% replacement showed superior strength compared to a 10% replacement, and the 10% replacement was stronger than a 0% cement replacement. Notably, the 20% cement replacement displayed negative over-strength percentages, specifically -2.42% in compressive strength and -1.42% in flexural strength on the 28th day. This deviation raises concerns about its suitability for use in concrete applications, signifying that a 20% replacement may not be recommended.

In this current study, graphene oxide (GO) was incorporated to the fibre reinforced concrete (FRC), to investigate the synergetic effect on physical, mechanical and microstructural properties. A comprehensive investigation was made with both cement mortar and concrete with distinct mixes incorporating varying dosages of GO – up to 0.08%, SF (micro-steel fibre) up to 0.8% and selecting the ideal dosage from the preliminary test for GO+SF combination in cementitious composite. Non-destructive test of ultrasonic pulse velocity (UPV) is carried out after standard curing time. Compressive and split tensile strength were carried out for the samples cured up to 28 days and showed a significant enhancement of strength with inclusion of both GO and SF. The ideal dosage for the combination of GO+SF (0.06% + 0.5%) is confirmed to assess the synergistic effect, the findings exhibited an enhanced compressive strength by 59.4%. The UPV values of the different mixes stating the quality and homogeneity of matrix are well correlated with the compressive strength results, Thus, confirming the reliability of UPV test on evaluating the mechanical performance of concrete. The internal microstructure and morphology of the composite has been scrutinized by advanced techniques of FE-SEM and Micro-CT scan, resulted in observing the matrix and finding out the increased hydration, enhanced denser products and reduced porosity. The results facilitated an in-depth understanding of the impact of nano-microfibre in cementitious composites as well as an intriguing nano-micro material which could meet the evolving needs of building materials utilized in construction industry.

The study focuses on the development of cementitious composites using 3D printing and plastic waste as a sustainable aggregate substitute. This study involves experimenting with various percentages of plastic waste as a partial substitute for ground granulated blast furnace slag (GGBFS) in a control mix. The study examines the anisotropy of the 3D printing process, comparing it with properties of mold-cast samples. In addition, it assesses the fire resistance and mechanical properties of samples at elevated temperatures (100 °C, 300 °C, and 600 °C). Key mechanical properties, including 28-day compressive stress and flexural strength, are determined through experimental testing using a standard compression test and three-point bending test. The study also considers the modulus of elasticity (MOE) in compressive tests to evaluate a sample’s ability to deform elastically and the flexural toughness index to assess energy absorption and crack resistance of flexural samples. Following the experimental testing, the study’s key findings suggest that significant mass loss occurred at 300 °C and above, with plastic samples demonstrating increased mass loss at 600 °C. At 600 °C, plastic degradation led to the formation of voids and cracks within samples due to heightened internal pressure. Anisotropy was evident in 3D-printed samples, with loads parallel to the layer direction resulting in greater compressive strength and MOE. Furthermore, layer direction parallel to the longitudinal axis of flexural samples yielded higher flexural strength and flexural toughness. Mold-cast samples displayed superior compressive strength and stiffer behavior, with higher MOE compared to 3D-printed samples. However, 3D-printed plastic samples exhibited superior flexural strength compared to mold-cast samples, attributed to the alignment of plastic within the samples. The study also observed a reduction in compressive strength with the addition of plastic, explained by the poor bonding of plastic with cement due to its hydrophobic nature. Despite this, flexural strength generally improved with plastic addition, except at 600 °C, where plastic samples showed significant degradation in both compressive and flexural strength due to plastic degradation within the samples.