scholarly journals APPLICATION OF GRAPHENE OXIDE IN CEMENTITIOUS COMPOSITES FOR CEMENT CONTENT REDUCTION

2018 ◽  
Vol 1 (1) ◽  
pp. 4-9
Author(s):  
Renan Pícolo Salvador ◽  
Roberto Munhoz Bueno ◽  
Dimas Alan Strauss Rambo ◽  
Sandro Martini

Cement production is responsible for 5% of CO2 emissions worldwide. The concern about the pollution derived from the construction industry has brought attention to the need of developing more sustainable construction materials and processes. Admixtures based on nanometric graphene oxide have the potential to enhance mechanical properties and durability of cementitious composites. In this context, an experimental program was conducted to evaluate how the addition of graphene oxide may be used to reduce cement content in concretes, maintaining the same mechanical properties of conventional concretes (control matrices, with no graphene oxide additions). Kinetics of hydration of cement pastes was evaluated by isothermal calorimetry, phase evolution during hydration was determined by X-ray diffraction coupled with quantitative Rietveld analysis and mechanical properties were evaluated by compressive strength. Results indicate that graphene oxide additions provide a faster hydration rate until 24 h and generate a larger amount of C-S-H gel, increasing mechanical strength of the matrix. By the addition of graphene oxide dispersion (0.4% of solid content) at 0.02% by cement weight, cement content reductions of up to 15% may be achieved, maintaining the same compressive strength as the control matrices. From this research, a reduction in cement content to obtain more sustainable construction materials and processes may be achieved.

2014 ◽  
Vol 980 ◽  
pp. 91-96
Author(s):  
O.A. Johnson ◽  
Napiah Madzlan ◽  
Ibrahim B. Kamaruddin

In the recent years there has been an intensification of policies on sustainable construction materials in the construction industry. This environmental policy has brought about development of various sustainable materials in which Petrovege blocks is one of the outstanding products. This paper investigates the effect of curing age on the compressive strength of the product. Block samples were prepared by adding 8%, 9%, 10%, 11%, 12%, and 13% liquid content of the mixture of vegetable oil and crude oil sludge as a binder after the optimum liquid content has been established. The specimens were cured at different period of time of 48hrs, 72hrs, 96hrs, and 120hrs. Mechanical properties of the products were evaluated. Compressive strength of Petrovege samples varies from 5.31 N/mm2to 18.88 N/mm2indicating that the compressive strength increases with increase in curing age, while decrease in porosity leads to increased compressive strength for the stipulated curing ages. All samples satisfied the minimum requirements in terms of compressive strength, in accordance with all available standards.


2021 ◽  
Vol 13 (7) ◽  
pp. 1289-1294
Author(s):  
Jin Kim ◽  
Young-Ho Kim ◽  
Jong-Young Lee ◽  
Jung-Geun Han

ABSTRACTThe modern society is a world made of concrete. Many buildings, ports, dams, and other infrastructure are made of concrete. Concrete is mainly composed of aggregate and cement. It is mixed with blended water and used after curing. This study used porous feldspar known to react well with cement to replace fine aggregate and reduce cement content. Although feldspar mortar reduced cement content by 5% (25%–>20%), the compressive strength increased 1.4 to 2.9 times compared to its counterpart, Ready-Mixed Mortar (RMM). Using Hydrogen Nano-Bubble Water (HNBW) as blended water, compressive strength was increased from 7% to a maximum of 23%. This proved that hydrogen nano-bubble water could promote cement hydrate creation and reaction. When hydrogen nano-bubble water was used as blended water, thermal conductivity decreased by a maximum of 30% compared to the use of plain water as blended water. Results of this study indicate that construction materials with improved thermal efficiency could be developed.


2021 ◽  
Vol 11 (11) ◽  
pp. 4754
Author(s):  
Assia Aboubakar Mahamat ◽  
Moussa Mahamat Boukar ◽  
Nurudeen Mahmud Ibrahim ◽  
Tido Tiwa Stanislas ◽  
Numfor Linda Bih ◽  
...  

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).


2020 ◽  
Vol 234 ◽  
pp. 111709 ◽  
Author(s):  
Su-Jin Lee ◽  
Seong-Hoon Jeong ◽  
Dong-Uk Kim ◽  
Jong-Pil Won

2020 ◽  
Vol 13 (1) ◽  
pp. 45-53
Author(s):  
Sajid Kamil Zemam

This study seeks to develop a sustainable construction technique based on the introduction of a specific method for improving concrete compressive strength through a proposed multi-vibration compaction method. An experimental program is performed to evaluate the effect of the proposed compaction technique on fresh silica fume concrete undergoing the initial setting. Multi-vibration intends to minimize concrete production cost because it upgrades the compressive strength of the same materials with better utilization of the vibration energy required for compaction. The collected experimental data presented assign relationships among vibration duration, vibration cycles or phases, and compressive strength upgrading of single vibrated, revibrated, and multi-vibrated specimens for analysis and discussion. This study shows that multi-vibration phases, rather than single vibration or revibration techniques, are powerful techniques for improving concrete compressive strength. The results indicated that the existence of an optimum multi-vibration mode was dominated by phase number and vibration duration and confirm the reliability vibration overall time duration recommended by ACI 309 which relates to a single vibration time limit to be considered in the case of multi vibration technique. Multi-vibration Mode 8 (subjected to three vibration phases 10, 20, and 30 sec ) has the best effect for the considered mixtures among the specific vibration modes. The maximum improvement ratio is 1.25, which is associated with the plastic mixture.   


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247599
Author(s):  
Yingjun Jiang ◽  
Jiangtao Fan ◽  
Yong Yi ◽  
Tian Tian ◽  
Kejia Yuan ◽  
...  

The vertical vibration compaction method (VVCM), heavy compaction method and static pressure method were used to form phyllite specimens with different degrees of weathering. The influence of cement content, compactness, and compaction method on the mechanical properties of phyllite was studied. The mechanical properties of phyllite was evaluated in terms of unconfined compressive strength (Rc) and modulus of resilience (Ec). Further, test roads were paved along an expressway in China to demonstrate the feasibility of the highly weathered phyllite improvement technology. Results show that unweathered phyllite can be used as subgrade filler. In spite of increasing compactness, phyllite with a higher degree of weathering cannot meet the requirements for subgrade filler. With increasing cement content, Rc and Ec of the improved phyllite increases linearly. Rc and Ec increase by at least 15% and 17%, respectively, for every 1% increase in cement content and by at least 10% and 6%, respectively, for every 1% increase in compactness. The higher the degree of weathering of phyllite, the greater the degree of improvement of its mechanical properties.


Engineered cementitious composites (ECC) are a type of high-performance fiber reinforced cementitious composite. ECC has different applications in the construction field due to its inherent characteristics of high tensile strain. The main concern regarding ECC is its high cost. The content of cement is high contributing to its cost. In this research work, the cement in ECC is replaced with marble dust and its mechanical properties such as compressive strength and flexure strength have been assessed. For this purpose, both cubes and cylinders were tested at different test ages for finding the compressive strength development with time and observe the shape effect of specimens on the compressive strength of ECC mixes. Beam members were tested for finding the flexure strength of ECC mixes. Deflection gauge was also installed at the mid span on the bottom surface of the beams to find the maximum mid span deflection before failure. The compression test results of both cylinders and cubes revealed that using of marble dust has negative effect on the compressive strength of ECC. The flexure strength result showed that marble dust can be used up to some extent replacing cement will increase the flexure strength. The result of mid span deflection suggests that by incorporating marble dust in ECC, its ductility increases.


Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1707 ◽  
Author(s):  
Yu-You Wu ◽  
Longxin Que ◽  
Zhaoyang Cui ◽  
Paul Lambert

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.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Kun Zhang ◽  
Bairu Lu ◽  
Yihong Wang ◽  
Zhijun Lei ◽  
Zhanshen Yang

According to the latest UN statistics, more than 2 billion people in the world still live in various forms of earthen buildings, including some in China. The variety of earth-based constructional materials is significant among different regions, with each region influencing the selection of local earth construction materials. In this study, earth materials from four regions of China were collected and sorted, with 10 samples from each source, and cube compressive strength tests were performed to analyze the composition and mechanical properties of the four materials, including northeast black earth, southeast red earth, northwest loess, and Xinjiang yellow sand earth. The results showed that significant differences existed in the composition of earth-based constructional materials from different regions, which have influence on the materials’ compressive strength. The order from large to small of compressive strengths was loess, black earth, yellow sandy earth, and red earth. Material load-displacement curves were influenced significantly by the plasticity index, but the overall failure processes of the various samples were basically the same.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1035 ◽  
Author(s):  
Afsaneh Valizadeh ◽  
Farhad Aslani ◽  
Zohaib Asif ◽  
Matt Roso

Heavyweight self-compacting concrete (HWSCC) and heavyweight geopolymer concrete (HWGC) are new types of concrete that integrate the advantages of heavyweight concrete (HWC) with self-compacting concrete (SCC) and geopolymer concrete (GC), respectively. The replacement of natural coarse aggregates with magnetite aggregates in control SCC and control GC at volume ratios of 50%, 75%, and 100% was considered in this study to obtain heavyweight concrete classifications, according to British standards, which provide proper protection from sources that emit harmful radiations in medical and nuclear industries and may also be used in many offshore structures. The main aim of this study is to examine the fresh and mechanical properties of both types of mixes. The experimental program investigates the fresh properties of HWSCC and HWGC through the slump flow test. However, J-ring tests were only conducted for HWSCC mixes to ensure the flow requirements in order to achieve self-compacting properties. Moreover, the mechanical properties of both type of mixes were investigated after 7 and 28 days curing at an ambient temperature. The standard 100 × 200 mm cylinders were subjected to compressive and tensile tests. Furthermore, the flexural strength were examined by testing 450 × 100 × 100 mm prisms under four-point loading. The flexural load-displacement relationship for all mixes were also investigated. The results indicated that the maximum compressive strength of 53.54 MPa was achieved by using the control SCC mix after 28 days. However, in HWGC mixes, the maximum compressive strength of 31.31 MPa was achieved by 25% magnetite replacement samples. The overall result shows the strength of HWSCC decreases by increasing magnetite aggregate proportions, while, in HWGC mixes, the compressive strength increased with 50% magnetite replacement followed by a decrease in strength by 75% and 100% magnetite replacements. The maximum densities of 2901 and 2896 kg/m3 were obtained by 100% magnetite replacements in HWSCC and HWGC, respectively.


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