scholarly journals Property Improvement of Cement Emulsified Asphalt Paste Modified by Graphene Oxide

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yu-wei Ma ◽  
Hong-yan Zhao ◽  
Gang Li ◽  
Zhen-jun Wang ◽  
Hua Tang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Building Material ◽  
Cement Hydration ◽  
Setting Time ◽  
Hydration Products ◽  
Hummers Method ◽  
The Stability ◽  
Emulsified Asphalt

Cement emulsified asphalt paste (CEAP) is widely used as a construction and building material by combining the advantages of cement rigidity and asphalt flexibility. However, the properties of CEAP can be evidently reduced due to the addition of emulsified asphalt. In this work, graphene oxide (GO) was prepared by the Hummers method and was innovatively used to improve the workability and strength of CEAP. The viscosity of CEAP was tested by Brookfield viscometer. In addition, the effects of GO on the setting time of CEAP were studied. The adsorption between cement and asphalt with GO was tested through an ultraviolet-visible spectrophotometer and the stability of CEAP was tested by zeta potentiometer. The effects of GO on the strength of CEAP were studied. The reinforcement effects of GO on CEAP were analyzed. The results show that the viscosity of CEAP and cement hydration products can increase after adding a reasonable dosage of GO to CEAP. The setting time of CEAP first decreases and then increases with the increase of GO dosage. The adsorption and viscosity of cement and asphalt increase with the increase of GO dosage. GO can reduce CEAP stability and make the paste easier to agglomerate. The flexural strength and the compressive strength of CEAP at 28 curing days first increase and then decrease with the increase of GO dosage, but excessive GO can hinder cement hydration. The reasonable dosage of GO in CEAP can be determined as 0.06% in asphalt weight.

Study on Effect and Action Mechanism of Different Superplasticizer on Properties of Titanium Gypsum

2013 ◽  
Vol 468 ◽  
pp. 24-27
Author(s):  
Chuan Wei Du ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Chemical Modification ◽  
Mechanical Strength ◽  
Setting Time ◽  
Test Results ◽  
Hydration Products ◽  
Action Mechanism ◽  
Micro Structure ◽  
Modification Of Titanium

The chemical modification of titanium gypsum was made by calcium lignosulfonate, naphthalene and polycarboxylate superplasticizer. The effect of different superplasticizer on the physical properties of titanium gypsum was studied. The test results show that the standard consistency water, setting time and mechanical strength of titanium gypsum had changed to different extent with the three types of superplasticizer added. Naphthalene superplasticizer had best modification effect on titanium gypsum and its optimum content was 3%. When the naphthalene superplasticizer dosage was 3%, the 2h flexural strength and the 2h compressive strength of sample were 1.15MPa and 2.37MPa. The micro structure of titanium gypsum hydration products was analysed by SEM and the action mechanism of superplasticizer was analysed.

Influence of Triethanolamine on the Properties of Cement-Based Materials

2017 ◽  
Vol 898 ◽  
pp. 2010-2017 ◽  
Author(s):  
Xiao Ying Wang ◽  
Ming Zhang Lan ◽  
Wei Fang Hou ◽  
Bin Feng Xiang ◽  
Xu Dong Zhao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Hydration ◽  
Setting Time ◽  
Cementitious Materials ◽  
Hydration Products ◽  
Initial Setting Time ◽  
Final Setting Time ◽  
Retarding Effect ◽  
Initial Setting

The effects of triethanolamine on the compressive strength and setting time of fly ash cementitious materials, slag cementitious materials, and limestone cementitious materials were investigated. The results show that the dosage of 0.04% of triethanolamine can significantly improve the 3d, 7d and 28d compressive strength of fly ash cementitious materials. It possesses less impact on the setting time. The dosage of 0.04% of triethanolamine can significantly improve the 3d and 7d compressive strength of slag cementitious materials while the effect of late strength is not obvious. It extends the initial setting time and the final setting time is not changed, which has retarding effect. The results of hydration heat and XRD show that triethanolamine extends the induction period of cement hydration, and gypsum is exhausted in advance during the hydration process. Triethanolamine promotes the transformation of AFt to AFm and there is no effect on the type of hydration products.

Effect of Metakaolin on Geopolymer Industry

2019 ◽  
pp. 49-70
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Reaction Mechanisms ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Experimental Studies ◽  
Acid Attack ◽  
Repair Materials ◽  
Hardened State

This chapter discusses the effects of metakaolin (MK) on geopolymer mortar and concrete industries. The research topics of MK-based geopolymer cover reaction mechanisms and kinetics. This chapter aims at augmenting knowledge about enhancing mechanical properties of geopolymer mortars/concrete using MK. Specifically, this chapter presents literature studies as well as current experimental studies which delineate the effect of MK on fresh and hardened-state properties of geopolymer mortars (GPMs). Properties and characteristics of metakaolin are explained followed by properties of fresh MK mortars. Properties of hardened MK concrete and durability aspects of MK mortars are explained. Applications of MK-based geopolymers and metakaolin-based geopolymers as repair materials are also included in this chapter. The results of using MK-based GPMs revealed improved workability, enhanced setting time, increased density, higher compressive strength, flexural strength, and resistance against acid attack than conventional ordinary portland cement mortar/concrete.

scholarly journals Effect of Soda Residue Addition and Its Chemical Composition on Physical Properties and Hydration Products of Soda Residue-Activated Slag Cementitious Materials

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1789 ◽  
Author(s):  
Yonghui Lin ◽  
Dongqiang Xu ◽  
Xianhui Zhao
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Cementitious Materials ◽  
Aluminum Silicate ◽  
Chemical Components ◽  
Main Role ◽  
Hydration Products ◽  
Granulated Blast Furnace Slag ◽  
Activated Slag ◽  
Main Components

Soda residue (SR), the solid waste of Na2CO3 produced by ammonia soda process, pollutes water and soil, increasing environmental pressure. SR has high alkalinity, and its main components are Ca(OH)2, NaCl, CaCl2, CaSO4, and CaCO3, which accords with the requirements of being an alkali activator. The aim of this research is to investigate the best proportion of SR addition and the contribution of individual chemical components in SR to SR- activated ground granulated blast furnace slag (GGBS) cementitious materials. In this paper, GGBS pastes activated by SR, Ca(OH)2, Ca(OH)2 + NaCl, Ca(OH)2 + CaCl2, Ca(OH)2 + CaSO4, and Ca(OH)2 + CaCO3 were studied regarding setting time, compressive strength (1 d, 3 d, 7 d, 14 d, 28 d), hydration products, and microstructure. The results demonstrate that SR (24%)-activated GGBS pastes possess acceptable setting time and compressive strength (29.6 MPa, 28 d), and its hydration products are calcium silicate hydrate (CSH) gel, calcium aluminum silicate hydrates (CASH) gel and Friedel’s salt. CaCl2 in SR plays a main role in hydration products generation and high compressive strength of SR- activated GGBS pastes.

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 Structural Performance of Translucent Concrete Façade Panels

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Awetehagn Tuaum ◽  
Stanley Shitote ◽  
Walter Oyawa ◽  
Medhanye Biedebrhan
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bulk Density ◽  
Optical Fibers ◽  
Building Material ◽  
Energy Demand ◽  
Volume Ratio ◽  
Structural Performance ◽  
Artificial Lighting ◽  
Plastic Optical Fibers

Energy conservation is an emerging global issue for sustainable infrastructure development. The building sector energy demand accounts for approximately 34% of the world’s energy demand, and artificial lighting consumes around 19% of the total delivered electricity globally. Developing a new kind of building material that can reduce the demand for artificial lighting energy is vital. This research attempts to address such issues through the development of translucent concrete façade using locally available materials that can be used as energy-saving building material. Bulk density, compressive strength, and flexural strength of translucent concrete containing 2%, 4%, and 6% volume ratios of plastic optical fibers (POF) were studied. Moreover, the flexural toughness of translucent concrete façade panels integrating 6% volume ratio of POF was also investigated. The experimental results showed that using up to 6% volume ratio of plastic optical fibers had no adverse effect on the bulk density of translucent concrete. Translucent concrete specimens exhibited relatively lower compressive and flexural strengths compared to the reference concrete. However, it was evidently observed that the compressive strength of translucent concrete increased with increasing the volume ratio of POF. The flexural strength of translucent concrete was observed to decline with increase in the volume ratio of POF. Results demonstrated that translucent concrete panels have better flexural toughness, ductility, and energy absorption capacity than the reference concrete panel. The energy-saving, environmental conservation, and aesthetic and structural performance improvements stemming from the application of translucent concrete façade panel as architectural wall would foster the development of green and resilient buildings as well as contribute to sustainable construction.

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.

scholarly journals Effect of basalt powder addition on properties of mortar

2019 ◽  
Vol 262 ◽  
pp. 06002 ◽  
Author(s):  
Magdalena Dobiszewska ◽  
Waldemar Pichór ◽  
Paulina Szołdra
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Beneficial Effect ◽  
Cement Paste ◽  
Cement Hydration ◽  
Asphalt Mixture ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Freeze Resistance ◽  
Powder Addition

The study evaluates the use of waste basalt powder as a replacement of cement to enhance hydration of cement and mortar properties. The basalt powder is a waste resulting from preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in adding the powder waste as a partial replacement of cement. The percentages of basalt powder in this research are 0-40% and 0-20% by mass of cement in the pastes and mortars respectively. The experiments were carried out to determine the influence of basalt powder on cement hydration, as well as compressive and flexural strength. Results indicate that addition of basalt powder as a replacement of cement leads to deterioration of compressive strength. The flexural strength of mortar is improved in some cases. Waste basalt powder only slightly influences the cement hydration.

scholarly journals Mechanical Properties and Shrinkage Behavior of Concrete-Containing Graphene-Oxide Nanosheets

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 590 ◽  
Author(s):  
Zengshun Chen ◽  
Yemeng Xu ◽  
Jianmin Hua ◽  
Xu Wang ◽  
Lepeng Huang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Elasticity Modulus ◽  
Shrinkage Strain ◽  
Graphene Oxide Nanosheets ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Dry Shrinkage ◽  
Shrinkage Behavior

Graphene oxide (GO) has been widely used as an additive due to its numerous unique properties. In this study, the compressive strength, flexural strength and elasticity modulus of concrete containing 0.02 wt%, 0.05 wt % and 0.08 wt % GO, and its dry shrinkage performance have been experimentally investigated. After the sample preparation, apparatus for compression test and flexural test were used to test the relevant properties of concrete containing GO. The dial indicators were used to measure the shrinkage of samples. The results indicate that GO can considerably improve the compressive strength, flexural strength, and elasticity modulus of concrete at the concrete age of 28 days by 4.04–12.65%, 3.8–7.38%, and 3.92–10.97%, respectively, which are substantially smaller than the increment at the age of 3 d by 5.02–21.51%, 4.25–13.06%, and 6.07–27.45% under a water-cement ratio of 0.35. It was also found that GO can increase the shrinkage strain of concrete. For example, at the age of 60 days, 0.02 wt%, 0.05 wt% and 0.08 wt% GO can increase the shrinkage strain of ordinary concrete by 1.99%, 5.79% and 7.45% respectively under a water-cement ratio of 0.49. The study has advanced our understanding on mechanical and shrinkage behavior of concrete containing GO.

scholarly journals Crossover Effect in Cement-Based Materials: A Review

2019 ◽  
Vol 9 (14) ◽  
pp. 2776 ◽  
Author(s):  
Sumra Yousuf ◽  
Payam Shafigh ◽  
Zainah Ibrahim ◽  
Huzaifa Hashim ◽  
Mohammad Panjehpour
Keyword(s):  
Compressive Strength ◽  
Construction Industry ◽  
Building Materials ◽  
Cement Hydration ◽  
Curing Temperature ◽  
Future Research ◽  
Hydration Products ◽  
Crossover Effect ◽  
Cement Based Materials ◽  
Mineral Compositions

Cement-based materials (CBMs) such as pastes, mortars and concretes are the most frequently used building materials in the present construction industry. Cement hydration, along with the resulting compressive strength in these materials, is dependent on curing temperature, methods and duration. A concrete subjected to an initial higher curing temperature undergoes accelerated hydration by resulting in non-uniform scattering of the hydration products and consequently creating a great porosity at later ages. This phenomenon is called crossover effect (COE). The COE may occur even at early ages between seven to 10 days for Portland cements with various mineral compositions. Compressive strength and other mechanical properties are important for the long life of concrete structures, so any reduction in these properties is of great concern to engineers. This study aims to review existing information on COE phenomenon in CBMs and provide recommendations for future research.

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