scholarly journals Hydration of Calcium Sulfoaluminate-Based Binder Incorporating Red Mud and Silica Fume

2019 ◽  
Vol 9 (11) ◽  
pp. 2270 ◽  
Author(s):  
Yubin Jun ◽  
Jae Hong Kim ◽  
Taewan Kim
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Red Mud ◽  
Drying Shrinkage ◽  
Pozzolanic Activity ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Replacement Level ◽  
Calcium Sulfoaluminate ◽  
Expansive Agent

This study investigated the properties of hardened pastes made with calcium sulfoaluminate expansive agent (CSA), red mud, and silica fume. Five different ratios of 10:90, 20:80, 30:70, 40:60, and 50:50 were applied as the weight ratios of CSA and red mud. Red mud was replaced with 0, 5, and 10% silica fume by weight. Compressive strength, drying shrinkage, XRD, MIP, and SEM/EDS of the hardened pastes were performed. The results indicated that as the amount of CSA increased (i.e., as the amount of red mud decreased) up to 30%, sample strengths showed a tendency to increase. The main reaction product of the pastes was expansive ettringite, which was formed from the consumption of ye’elimite, anhydrite, gypsum, and Ca(OH)2. It was expected that C-S-H would be formed by the reaction of C2S in red mud; however, C-S-H phase was not present, and the pozzolanic activity due to the use of silica fume did not occur. The increase of CSA replacement level was effective for controlling the drying shrinkage of the samples. However, 50% replacement level of CSA induced excessive expansion, leading to the reduction in strength. It was found that the excessive expansion in the sample was reduced by the addition of silica fume.

Effect of Steel Slag on Shrinkage Characteristics of Calcium Sulfoaluminate Cement

2021 ◽  
Vol 1036 ◽  
pp. 263-276
Author(s):  
Hao Ran Huang ◽  
Yi Shun Liao ◽  
Siraj Ai Qunaynah ◽  
Guo Xi Jiang ◽  
Da Wei Guo ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Relative Humidity ◽  
Cement Paste ◽  
Steel Slag ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Slag Content

The effects of steel slag with 0, 10%, 20 % and 40% content on the chemical shrinkage, autogenous shrinkage, internal relative humidity, and drying shrinkage of calcium sulfoaluminate cement paste were studied. The results show that the compressive strength of calcium sulfoaluminate cement paste at an early stage decreases gradually when the content of steel slag increases. When the steel slag content is 0 and 10%, the compressive strength of hardened cement pastes gradually decreases at 90 and 180 days, but the samples with steel slag content of 20% and 40% maintain the compressive strength growth within 180 d. With the extension of curing period, the gap of compressive strength is gradually narrowed. The autogenous shrinkage decreases with the increase of steel slag content and has a good linear relationship with the relative humidity inside the paste. The proportion of autogenous shrinkage to chemical shrinkage is deficient, and most chemical shrinkage occurs in the form of the pore volume. Although the trends of drying shrinkage and autogenous are consistent, the former is more severe than the latter.

Dry Shrinkage and Compressive Strength of Blended Cement Pastes with Fly Ash and Silica Fume

2012 ◽  
Vol 535-537 ◽  
pp. 1735-1738 ◽  
Author(s):  
Yan Li ◽  
Dao Sheng Sun ◽  
Xiu Sheng Wu ◽  
Ai Guo Wang ◽  
Wei Xu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Blended Cement ◽  
Drying Shrinkage ◽  
Cementitious Material ◽  
Strength Increase ◽  
Cement Pastes ◽  
Dry Shrinkage

This paper reports the drying shrinkage and compressive strength results of cement pastes with fly ash and silica fume. In this study, Portland cement (PC) was used as the basic cementitious material. Fly ash (FA) and silica fume (SF) were used as cement replacement materials at levels of 0%, 5%, 10%, and 15% , 40%, 35%, 25%, and 15% by weight of the total cementitious material, respectively. The water/cement (PC + FA + SF) ratios (w/c) was 0.28 by weight. The samples produced from fresh pastes were demoulded after a day; then they were cured at 20 ±1°C with 50 ± 3% relative humidity (RH) until the samples were used for drying shrinkage and compressive strength measurement at various ages. The results show that drying shrinkage and compressive strength increase with increasing SF content, and the optimum composition of blended cement pastes is the cement paste with 30% fly ash and 10% silica fume, which possesses lower drying shrinkage values than that of plain cement paste and higher early age strength than that of blended cement pastes with fly ash. Furthermore, a linear relationship is established between compressive strength and drying shrinkage. By comparing the development of compressive strength and the drying shrinkage deformations, it appears possible to predict the drying shrinkage according to the acquired compressive strength.

scholarly journals Effects of Shrinkage Reducing Agent and Expansive Admixture on the Volume Deformation of Ultrahigh Performance Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Su Anshuang ◽  
Qin Ling ◽  
Zhang Shoujie ◽  
Zhang Jiayang ◽  
Li Zhaoyu
Keyword(s):  
Compressive Strength ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Reducing Agent ◽  
Cementitious Material ◽  
Volume Deformation ◽  
Air Content ◽  
Expansive Agent ◽  
Reduction Effect ◽  
Shrinkage Reducing Agent

This paper investigated the influences of shrinkage reducing agent and expansive admixture on autogenous and drying shrinkage of ultrahigh performance concrete (UHPC) containing antifoaming admixture. The shrinkage reducing agent was used at dosage of 0.5%, 1%, and 2% and the expansive admixture was used at dosage of 2% to 4% by mass of cementitious material. The results show that the air content of UHPC increases with the higher addition of shrinkage reducing agent and expansive admixtures. However, the fluidity, compressive strength, and shrinkage of UHPC exhibit a declining tendency. The usage of expansive agent at dosage of 4% significantly reduces the shrinkage of UHPC. The 7-day autogenous shrinkage was decreased by 16.0% and 28-day drying shrinkage was decreased by 29.5%, respectively. Shrinkage reducing agent at dosage of 2% reduced the 7-day autogenous shrinkage by 44.3% and 28-day drying shrinkage by 50.2%. Compared with expansive admixture, shrinkage reducing agent exhibits more efficient shrinkage reduction effect on UHPC.

scholarly journals Effect of Dolomite as Expansive Agent and Shrinkage Reducing Admixture in Self-Compacting Shrinkage – Compensating Concrete

2018 ◽  
Vol 26 (5) ◽  
pp. 1-8
Author(s):  
Qosai Sahib Radi Marshdi ◽  
Ahlam Hamid Jasim ◽  
Haider Abass Obeed
Keyword(s):  
Compressive Strength ◽  
Fresh Concrete ◽  
Drying Shrinkage ◽  
The Other ◽  
Restrained Shrinkage ◽  
Fresh Properties ◽  
Expansive Agent ◽  
Concrete Mixtures ◽  
Shrinkage Reducing Admixture ◽  
Compressive Strength Of Concrete

The principle of using expansive agents has been recommended to manufacture shrinkage compensating concrete provided that an adequate wet curing is carried out. On the other hand, shrinkage-reducing admixture (SRA) in the concrete mixes, has been more recently suggested to reduce the risk of cracking in concrete structures caused by drying shrinkage. This paper is devoted to the study of the influence of complex modifier in the form of superplasticizer, shrinkage reducing admixture and expansive agent CaO- MgO-based on the fresh properties, hardening processand restrained shrinkage of Self-Compacting-Shrinkage-Compensating Concretes. The combined addition of shrinkage-reducing admixture with expansive agent has been found to be successful in producing shrinkage-compensating concrete. It should be noted also that the shrinkage reducing admixture slightly improve the workabilityof the fresh concrete mixtures but, it slightly reduces the early compressive strength of concrete.

scholarly journals An experimental study on production of high strength non-shrink grout containing fly ash

2021 ◽  
Vol 72 (4) ◽  
pp. 477-485
Author(s):  
Chi Dang Thuy
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Drying Shrinkage ◽  
High Strength ◽  
Fine Aggregate ◽  
Expansive Agent ◽  
Chemical Admixture ◽  
The University ◽  
The Given

Cement-based grouts are widely used thanks to its outstanding features such as high workability, non-separation, non-bleeding, easy to fulfill small gaps with complex shapes. This paper descrcibes the first phase of a series of laboratory experiments that examined the ability of production of self - levelling mortar at the University of Transport and Communications. The Portland cement-based grout incorporated superplasticizer, fly ash, fine aggregate, water along with expansion agent to match as closed as possible the given high strength non-shrink grout. The experimental study focused on the performance of non-shrink grouts regarding the flowability, expansion and bleeding, strengths and drying shrinkage of the test grout mixtures. The high range water reducer (HRWR) at dosage of 1% by weight of cement was used as a flowability modifying chemical admixture to prevent water segregation and leads to an increase in compressive strength. The parameter tests consist of water-cement ratios, and fixed dosages of superplasticizer and expansive agent. To examine the flowability of grout mortars, the flow cone test was applied. The flow cone test result indicated that there were three proportional of grouts that can meet the requirement of fluidity. The compressive strength of specimens was tested according to ASTM C349-14. It was concluded that the compositions of grouts at a water-cement ratio of from 0.29 to 0.33 have compressive strengths greater than 60 MPa. The tested specimens using the expansive agent with the dosage recommended by the manufacturer meet the non-shrinkage requirement of a grout. The experimental results have demonstrated the ability of production of high strength non-shrink grouts.

Evaluation on Roles of Activated Silicon and Aluminum Oxides for Formation of Geopolymer from Red Mud and Silica Fume

2018 ◽  
Vol 777 ◽  
pp. 513-517 ◽  
Author(s):  
Van Quang Le ◽  
Minch Quang Do ◽  
Minh Duc Hoang ◽  
Thanh Phong Dang ◽  
Thu Ha Bui ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Red Mud ◽  
Polymer Chains ◽  
Experimental Results ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Aluminum Oxides ◽  
X Ray ◽  
Softening Coefficient

In this study, the alkaline solutions (NaOH) with concentration from 1M to 10M, red mud (RM) and silica fume (SF) were used as reactors in geopolymer reactions. RM contains 7.40% SiO2 and 13.65% Al2O3, SF has 94.50% SiO2, but only the activated oxides can participate into the geopolymer reactions. The activity of the oxides was investigated by measuring the dissolution of RM and SF in different concentrations of NaOH. Characteristics of the geopolymer samples were tested for compressive strength and softening-coefficient, its microstructure was analyzed by using X – ray diffraction (XRD). The experimental results were indicated that activated SiO2 is the highest exist in SF. In the structure of geopolymers, the silica can be bonded directly to each other (Si-Si) or linked through “most” oxygen (Si-O-Si) to form independent polymer chains, while aluminum themselves cannot create independent polymer chains, it only can be replaced the Si atomic in Si-O-Si polymer chains (Si-O-Al), instead.

Performance and Mechanism Study on C50 Micro-Expansion Polypropylene Fiber Reinforced Anti-Cracking Pumping Concrete

2012 ◽  
Vol 535-537 ◽  
pp. 1837-1841
Author(s):  
Gao He
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Polypropylene Fiber ◽  
Drying Shrinkage ◽  
Mechanism Study ◽  
Split Tensile Strength ◽  
Expansive Agent ◽  
Performance And Mechanism

Based on the construction application of C50 anti-cracking pumping concrete, the influence of the polypropylene fiber and expansive agent on the concrete was studied. The workability, mechanical property, drying shrinkage and crack resistance of the pumping concrete and their mechanisms were tested. The results indicated that the workability achieve the standard of pumping concrete through increasing the dosage of polycarboxylic superplasticizers. The incorporation of polypropylene fiber and expansive agents has little influence on the compressive strength and elastic modulus, but will significantly enhance split tensile strength and decrease the drying shrinkage and cracking.

scholarly journals Development of Eco-Friendly Cement Using a Calcium Sulfoaluminate Expansive Agent Blended with Slag and Silica Fume

2021 ◽  
Vol 11 (1) ◽  
pp. 394
Author(s):  
Taewan Kim ◽  
Ki-Young Seo ◽  
Choonghyun Kang ◽  
Tak-Kee Lee
Keyword(s):  
Silica Fume ◽  
Mechanical Performance ◽  
Hydration Product ◽  
Early Age ◽  
Low Carbon ◽  
Calcium Sulfoaluminate ◽  
Mixing Ratios ◽  
Expansive Agent ◽  
Binder Ratio

This is an experimental study on the development of a low-carbon, eco-friendly cement containing a calcium sulfoaluminate expansive agent (CSAe), slag, and silica fume (SF). The cement to be developed has a low water/binder ratio (w/b) of 0.5 and is designed to be used for structural purposes, with focus on its mechanical performance. CSAe, slag, and SF were mixed at various mixing ratios. The main hydration product of the slag-based CSAe cement in the experiment was ettringite. Substituting less than 30% of CSAe showed a sufficient level of mechanical performance; that is, the material could be used as structural cement. SF controlled the excessive expansion of CSAe. However, since the developed slag-CSAe-SF cement has low early age (1 d) strength, follow-up research is needed for improvement.

scholarly journals Effects of the incorporation of residue of masonry on the properties of cementitious mortars

2020 ◽  
Vol 19 (3) ◽  
pp. 407-421
Author(s):  
Yimmy Fernando Silva ◽  
◽  
David A. Lange ◽  
Silvio Delvasto ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Activity Index ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Heat Of Hydration ◽  
Cementitious Material ◽  
Pozzolanic Activity ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Supplementary Cementitious Material

This paper presents results of an experimental study of a residue of masonry (RM), sampled from a construction and demolition waste (CDW), added as a supplementary cementitious material (SCM) to partially replace up to 50% of Portland cement in the preparation of mortars. The pozzolanic activity (fixed lime and strength activity index), setting time, heat of hydration, the (autogenous and drying) shrinkage and compressive strength tests were carried out. The results show how the RM has a positive activity because the increase of RM replacement level in the mortars generates a lower heat of hydration and autogenous and drying shrinkage. The fixed lime at 28 and 180 days, indicating that the RM exhibits in some degree pozzolanic activity and the Strength Activity Index (SAI) was 77.13% and 84.36% of the compressive strength of 100% OPC mortar at the 7 and 28 days respectively, which conformed to ASTM C311. These results indicate that RM should be considered appropriated for using as a supplementary cementitious material.

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