scholarly journals A Comparative Study on the Effects of Three Nano-Materials on the Properties of Cement-Based Composites

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 857
Author(s):  
Chao Fu ◽  
Chunyan Xie ◽  
Jing Liu ◽  
Xiuli Wei ◽  
Dake Wu
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Raw Materials ◽  
Construction Materials ◽  
Microscopic Analysis ◽  
Performance Comparison ◽  
Nano Materials ◽  
Experimental Conditions ◽  
Nano Sio2

The application of nano-materials to modify construction materials has become a research hotspot in recent years, but often different scholars use different research methods and reach different conclusions about the same material, which is not conducive to the performance comparison between different materials. In this paper, nano-SiO2, carbon nanotubes (CNTs) and nanocrystalline cellulose (NCC) were used as raw materials to prepare cement-based composites to compare the effects of the three nanomaterials on the mechanical and water absorption properties under the same experimental conditions, and their principles were investigated via The scanning electron microscope (SEM), X-Ray Diffraction (XRD) and other microscopic analysis testing methods. At the same time, strength benefit indexes are introduced to comprehensively evaluate the economics of the strength improvement provided by the three kinds of nanomaterial. The results show that doping with nano-SiO2, CNTs and NCC can promote the hydration process of cement effectively. The composite material exhibits excellent mechanical properties at the macro level because of the nucleation and filling effect of nano-SiO2, and the bridging and strengthening effects of CNTs and NCC. The compressive strength increased by 45.13%, 28.31% and 44.19% at 7d, and 23.09%, 18.40% and 23.40% at 28d. The flexural strength of 7d increased by 31.00%, 36.22 and 54.81%, and 14.91%, 22.23% and 30.46% at 28d. The water absorption is SiO2 < NCC < CNTs, and the nano-SiO2 is lower than the other two materials at least 15.54%. CNTs group has the lowest compressive strength benefit, which is 16.91 yuan/m3, and the lowest flexural strength benefit is NCC, which is 3.59 yuan/m3.

scholarly journals Effects of Carbonation on the Properties of Concrete

2019 ◽  
pp. 205-214
Author(s):  
Ikumapayi C. M. ◽  
Adeniji A. A. ◽  
Obisesan A. A. ◽  
Odeyemi O. ◽  
Ajayi J. A.
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Water Absorption ◽  
Research Work ◽  
Construction Materials ◽  
Accelerated Carbonation ◽  
Weight Changes ◽  
Carbonation Process

Concrete is one of the reliable, durable, economical and acceptable construction materials among the building and construction stakeholders worldwide. Performance of concrete could be threatened especially reinforced concrete by some processes such as corrosion, sulfate attack among others. Corrosion of reinforcement in reinforced concrete can be induced by carbonation process. Even though carbonation initiates corrosion, it has been gathered that carbonation could still be of immense benefits to building and construction industries if its mechanism of operation is understudied. This research work has therefore investigated the effect of carbonation on some selected mechanical properties of concrete such as compressive strength, flexural strength, water absorption and weight changes. Concrete cubes and beams of M15 grade with 0.5 % water-cement ratio were prepared and subjected to accelerated carbonation. Their compressive strength, flexural strength, water absorption and weight changes were determined in accordance with the relevant standards. The outcomes show that carbonation improves all the mechanical properties investigated. The use of carbonation can be positively explored in reinforced concrete provided there is adequate nominal cover.

Study on Waterproof and Water-Resistant Properties of Gypsum

2012 ◽  
Vol 476-478 ◽  
pp. 1585-1588
Author(s):  
Hong Pan ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Ordinary Portland Cement ◽  
Experimental Results ◽  
Softening Coefficient

The comprehensively modified effect of cement, VAE emulsion and self-made acrylic varnish on mechanical and water-resistant properties of gypsum sample was investigated and microstructure of gypsum sample was analyzed. Experimental results exhibit that absolutely dry flexural strength, absolutely dry compressive strength, water absorption and softening coefficient of gypsum specimen with admixture of 10% ordinary Portland cement and 6% VAE emulsion and acrylic varnish coated on its surface can respectively reach to 5.11MPa , 10.49 MPa, 8.32% and 0.63, respectively.

scholarly journals Effect of Curing Method on Properties of Lightweight Foamed Concrete

2018 ◽  
Vol 7 (2.29) ◽  
pp. 927 ◽  
Author(s):  
Bishir Kado ◽  
Shahrin Mohammad ◽  
Yeong Huei Lee ◽  
Poi Ngian Shek ◽  
Mariyana Aida Ab Kadir
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Water Absorption ◽  
Precast Concrete ◽  
Construction Materials ◽  
Splitting Tensile Strength ◽  
Structural Members ◽  
Lightweight Construction ◽  
Foamed Concrete ◽  
Curing Method

Lightweight construction is aimed to achieve a sustainable feature by reducing transportation frequency and construction materials usage during construction phase. Lightweight precast concrete may serve an alternative for the lightweight construction. There are rarely application can be found for structural members as lightweight panels always to be used for secondary or non-load bearing members. This paper presents an experimental study on properties (compressive strength, splitting tensile strength, water absorption) of lightweight foamed concrete (LFC) at two different curing methods. LFC with densities of 1500, 1700, and 1800 kg/m3, cement-sand ratio of 2:1 and water-cement ratio of 0.5 were investigated. The results showed LFC can be produced with the properties ofdensity range of 1500 to 1800 kg/m3 and corresponding compressive strength of 10 to 39 MPa. The higher the density of LFC, the less the water absorption for all the curing method considered, the highest and the lowest water absorption was 11.3% and 2.0% for 1500 kg/m3 cured in water and 1800 kg/m3 cured in air respectively. Compressive strength of LFC increases with age and density while water cured LFC has high compressive strength. Splitting tensile strength increases with density of LFC, but air cured LFC has more splitting tensile strength than water cured of the same density. The highest splitting tensile strength recorded was 3.92 MPa for 1800 kg/m3 cured in air, which was about 16% of its compressive strength at 28 days of curing age. These properties are important and can be applied to LFC precast structural members with air or water curing method which have less references for LFC in structural usage.  

scholarly journals Flow Mechanism and Strength Characteristics of Textile Reinforced Concrete Mixed with Colloidal Nano-SiO2

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ping Xu ◽  
Rui Shi ◽  
Chao Wang ◽  
Yuhao Cui ◽  
Minxia Zhang
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Silica Fume ◽  
Inhibitory Effect ◽  
Equal Mass ◽  
Textile Reinforced Concrete ◽  
Nano Sio2 ◽  
Four Point Bending ◽  
Concrete Filling

In order to develop textile reinforced concrete (TRC) with good flowability and strength, colloidal nano-SiO2 (CNS) is adopted to improve the performance of TRC. The flowability, compressive strength, flexural strength, and four-point bending tests of TRC matrix with CNS are carried out, and the changes of internal micromorphological characteristics of TRC matrix are analyzed by combining with scanning electron microscopy. The results show that the CNS has an inhibitory effect on the flowability of TRC matrix, and the greater the amount of admixture is, the smaller the slump expansion of TRC matrix is. The compressive strength and flexural strength of TRC matrix show a trend of increasing and then decreasing as the amount of CNS increases, and the compressive strength reaches the maximum at each age (7 d, 14 d, 28 d) when CNS and silica fume replace 5% cement by 1 : 4 equal mass. The flexural strength reaches the maximum at each age (7 d, 14 d, 28 d) when 5% cement is replaced by CNS and silica fume with 3 : 7 equal mass. The flexural strength increases with the increase of CNS admixture. It is found by electron microscope scanning that the incorporation of CNS consumes more Ca(OH)2, refines the Ca(OH)2 crystal size, and generates more C-S-H gels. These C-S-H gels are distributed in a net-like pattern inside the concrete, filling the internal pores, effectively densifying the interfacial transition zone between the cementitious material and the aggregates, and optimizing the internal structure.

scholarly journals Influences of shrinkage reducing admixture on the mechanical properties, drying shrinkage, water absorption and porosity of Portland cement mortar

2021 ◽  
Vol 15 (3) ◽  
pp. 55-67
Author(s):  
Nguyen Van Chinh
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Drying Shrinkage ◽  
Effective Porosity ◽  
Minor Effect ◽  
Wide Range ◽  
Shrinkage Reducing Admixture ◽  
A Minor

Drying shrinkage is the main cause of early age cracking of concrete and mortar. A wide range of research has been conducted to reduce the drying shrinkage, including using fibres or chemical admixtures. This paper investigated the effect of shrinkage reducing admixture on the flexural strength, compressive strength, drying shrinkage, water absorption and porosity of mortar. The mix compositions were ordinary Portland cement (OPC) : sand : liquid = 1: 1: 0.38 in which liquid consisted of water and shrinkage reducing admixture (SRA). SRA was used at the proportions of 2%, 4%, and 7% by weight of cement. The test results show that SRA reduces the flexural and compressive strengths of mortar. The reduction in flexural strength and compressive strength at 28 days is 14% and 25%, respectively at 7% SRA dosage. In addition, SRA significantly reduces the drying shrinkage and water absorption of mortar. At 7% SRA dosage, the drying shrinkage at 53 days is reduced by 60% while the water absorption rate at 24 hours is reduced by 54%. However, SRA has a minor effect on the pore size distribution, effective porosity, and cumulative intrusion volume of mortar.

scholarly journals Physical Properties of Concrete Containing Graphene Oxide Nanosheets

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1707 ◽  
Author(s):  
Yu-You Wu ◽  
Longxin Que ◽  
Zhaoyang Cui ◽  
Paul Lambert
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Portland Cement ◽  
Physical Properties ◽  
Ordinary Portland Cement ◽  
Construction Materials ◽  
Split Tensile Strength ◽  
Cement Pastes

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.

scholarly journals Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

2020 ◽  
Vol 40 (2) ◽  
Author(s):  
Daniela Eugenia Angulo-Ramírez ◽  
William Gustavo Valencia-Saavedra ◽  
Ruby Mejía de Gutiérrez
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Water Absorption ◽  
Blast Furnace Slag ◽  
Construction Materials ◽  
Chloride Ion ◽  
Chloride Permeability ◽  
Alkaline Activator ◽  
Furnace Slag

Concretes based on alkaliactivated binders have attracted considerable attention as new alternative construction materials, which can substitute Portland Cement (OPC) in several applications. These binders are obtained through the chemical reaction between an alkaline activator and reactive aluminosilicate materials, also named precursors. Commonly used precursors are fly ash (FA), blast furnace slag (GBFS), and metakaolin. The present study evaluated properties such as compressive strength, rate of water absorption (sorptivity), and chloride permeability in two types of alkaliactivated concretes (AAC): FA/GBFS 80/20 and GBFS/OPC 80/20. OPC and GBFS/OPC* concretes without alkaliactivation were used as reference materials. The highest compressive strength was observed in the FA/GBFS concrete, which reported 26,1% greater strength compared to OPC concrete after 28 days of curing. The compressive strength of alkaliactivated FA/GBFS 80/20 and GBFS/OPC 80/20 was 61 MPa and 42 MPa at 360 days of curing, respectively. These AAC showed low permeability to the chloride ion and a reduced water absorption. It is concluded that these materials have suitable properties for various applications in the construction sector.

scholarly journals The influence of cement-based composite materials on the performance of bridges: modification and optimization by nano-SiO2 material

2020 ◽  
Vol 15 (3) ◽  
pp. 409-413
Author(s):  
Cheng Zhu
Keyword(s):  
Compressive Strength ◽  
Composite Materials ◽  
Flexural Strength ◽  
Building Materials ◽  
Complex Environments ◽  
Nano Sio2 ◽  
Bending Resistance ◽  
Cement Based Materials ◽  
Different Content ◽  
Compression Resistance

Abstract Cement-based materials have been widely used in bridge construction. In order to further improve their performance, this study analyzed the modification and optimization functions of nano-SiO2 materials, designed test specimens with different content of nano-SiO2 and conducted experiments on their flow performance, compression resistance, bending resistance and impermeability. The results showed that the flow performance of the materials decreased and the impermeability decreased with the increase of nano-SiO2 content. The compressive strength and flexural strength are the best when the content of nano-SiO2 is 1%. On the whole, the best content of nano-SiO2 is 1%; when the content of nano-SiO2 is 1%, all the properties of the specimens are good, which is more conducive to the construction of bridges in various complex environments. The research in this paper has made some contributions to the further application of nano-SiO2 in the optimization of building materials, which is conducive to the better development of building materials.

scholarly journals Preparation of Portland Cement with Gold Ore Tailings

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Wang ◽  
Geng Yao ◽  
Xiangnan Zhu ◽  
Junxiang Wang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Hydration Product ◽  
Difficult Problem ◽  
Initial Setting Time ◽  
Gold Ore ◽  
Curing Age

The disposal of gold ore tailings (GTs) has been a very difficult problem for a long time. Thus, this study explored a new approach to the management of GTs by preparing Portland cement. Physical properties, reaction mechanisms, and hydration product types of cement prepared with GTs (C-GTs) and ordinary Portland cement (C-SS) were compared. X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscope energy-dispersive spectroscopy (SEM-EDS) analysis techniques were used to study the mineralogical phases of the clinker and raw materials, hydration product types, and microtopography. The consistency, setting time, flexural strength and compressive strength values of the cement samples (C-GTs and C-SS), and burnability of the raw materials were also studied. The burnability analysis indicated that GTs provided a higher reactivity. The XRD results showed that the clinker phases of the C-GTs were C3S, C2S, C3A, and C4AF. The XRD, TG, and SEM-EDS results showed that the hydration products were flaky calcium hydroxide, rod-shaped ettringite, and granular C-S-H gels. Its compressive strength and flexural strength were, respectively, 30.4 MPa and 6.1 MPa at the curing age of 3 days and 59.1 MPa and 9.8 MPa at the curing age of 28 days, which were slightly higher than those of the C-SS. Furthermore, the results showed that the consistency, initial setting time, and final setting time for the two kinds of cement were similar, which further suggested that GTs could be used to prepare Portland cement.

Study of Coconut Charcoal Powder and Egg Shell Powder as Partial Replacement to Fine Aggregates and Cement in Load Bearing Concrete Bricks

2020 ◽  
Vol 853 ◽  
pp. 120-125
Author(s):  
Airvin John C. Palacio ◽  
Nioro G. Furiscal ◽  
Katrina Mae L. Abalos ◽  
Dioven Angelo A. Alferez ◽  
Edmer A. Bade ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Construction Materials ◽  
Control Sample ◽  
Agricultural Wastes ◽  
Partial Replacement ◽  
Agriculture Sector ◽  
Coconut Charcoal ◽  
Fine Aggregates ◽  
Egg Shell

Waste disposal is one of the issues that plague the society. Philippines is an agricultural country due to its strategic location in the tropics. Because of this nature, the agriculture sector tends to produce a huge amount of waste that if not disposed properly could pose a threat to the society and to the environment. With the advancement of technology, it has been a challenge for researchers to improve the quality of construction materials that is used in the industry. Studies have been performed on the possibilities of incorporating agricultural wastes to various construction materials as a form of waste diversion. In order to address the problem with agricultural wastes as well as to improve the property of construction materials, a study on coconut waste and eggshell waste was conducted as a constituent in concrete brick production. In this study, the density, compressive strength as well as the water absorption of concrete bricks with coconut charcoal powder (CCP) and eggshell powder (ESP) as replacement for fine aggregates and cement was conducted. Different mix ratios (0%, 2.5%, 5%, 10% CCP with a constant value of 5% ESP in each mix ratio) were carried out and the results were compared to a control sample. From the results of the density test, the concrete bricks with 5% CCP and 5% ESP was the lightest at a density of 1678.184 kg/m3, it also showed the least water absorption at 8.58% and exhibited the highest compressive strength at 17.5 MPa.

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