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.

scholarly journals Volume Stability of Cement Paste Containing Limestone Fines

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 366
Author(s):  
Jamal Khatib ◽  
Rawan Ramadan ◽  
Hassan Ghanem ◽  
Adel Elkordi
Keyword(s):  
Cement Paste ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Total Period ◽  
Volume Stability ◽  
Cement Replacement ◽  
Binder Ratio ◽  
Limestone Fines ◽  
Water To Binder Ratio

The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss of water and chemical reactions. Incorporating limestone fines (LF) as a cement replacement can affect the shrinkage of the paste. To examine this effect, five paste mixes were prepared with 0, 5, 10, 15 and 20% LF as a cement replacement and with a water-to-binder ratio (w/b) of 0.45. Four volume stability tests were conducted for each paste: chemical, autogenous and drying shrinkage and expansion. Chemical shrinkage was tested each hour for the first 24 h and thereafter every 2 days for a total period of 90 days. The drying shrinkage, autogenous shrinkage and expansion were monitored every 2 days until 90 days. The results showed that replacing 15% LF enhanced the chemical shrinkage of the paste. However, autogenous shrinkage of the paste was found to increase between 0 and 10% LF and decline sharply at 15 and 20% LF. Drying shrinkage was found to increase with the increase in LF content. Expansion exhibited little variation between 0 and 10% LF and an increase for replacement above 15% LF. These results are discussed in terms of the formation of hydration products and self-desiccation due to hydration.

scholarly journals The Modeling Research on the Early-Age Shrinkage of UHPFRC in Different Curing Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Song Han ◽  
Yazhou Liu ◽  
Dan Liu ◽  
Mingzhe An ◽  
Ziruo Yu
Keyword(s):  
Relative Humidity ◽  
Pore Structure ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Calculation Model ◽  
Fiber Reinforced Concrete ◽  
Early Age ◽  
Chemical Shrinkage ◽  
Hydration Degree ◽  
Curing Conditions

The early-age shrinkage of ultra-high performance fiber reinforced concrete (UHPFRC) in dry, sealed, and soaked curing was systematically measured. The calculation model of early-age shrinkage was established based on the theory of shrinkage of cementitious materials. According to the results of the relative humidity, hydration degree, pore structure, and elastic modulus of hardened slurry, the shrinkage calculation model in different curing conditions was calibrated. The results show that the early-age shrinkage of UHPFRC can be divided into three parts: chemical shrinkage, autogenous shrinkage caused by self-drying, and drying shrinkage caused by external drying. Based on the degree of hydration, the chemical shrinkage model was established. Based on the pore structure, the hydration degree, and the relative humidity of hardened slurry, the autogenous shrinkage model was established by introducing the effective pore coefficient. The drying shrinkage model was established based on the internal humidity. According to the shrinkage of soaked samples, the calculated value of chemical shrinkage in sealed and drying conditions was calibrated. This research provides theoretical support for the structural design and engineering application of UHPFRC.

scholarly journals Effects of Reactive MgO on the Reaction Process of Geopolymer

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 526 ◽  
Author(s):  
Zhaoheng Li ◽  
Wei Zhang ◽  
Ruilan Wang ◽  
Fangzhu Chen ◽  
Xichun Jia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Size ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Reaction Process ◽  
Chemical Shrinkage ◽  
Uniform Expansion ◽  
Geopolymer Paste

In order to compensate for the shrinkage of geopolymer pastes uniformly, reactive MgO powders are evenly dispersed in the geopolymer. The deformation performance, mechanical properties, microstructure and components of geopolymer pastes with reactive MgO are characterized. The effects of the content and the activity of MgO are discussed. The results indicate that the chemical shrinkage, autogenous shrinkage and drying shrinkage decrease with the addition of reactive MgO. MgO reacted with water, and fine Mg(OH)2 crystals forms as a geopolymer paste. Mg(OH)2 produces uniform expansion, which refines the pore size of pastes and the compressive strength increases. The shrinkage of the geopolymer pastes is thus effectively compensated.

scholarly journals Effect of Supplementary Materials on the Autogenous Shrinkage of Cement Paste

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3367 ◽  
Author(s):  
Tianshi Lu ◽  
Zhenming Li ◽  
Hao Huang
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Relative Humidity ◽  
Cement Paste ◽  
Blast Furnace Slag ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Chemical Shrinkage ◽  
Internal Relative Humidity ◽  
Furnace Slag

In recent years more and more attention has been given to autogenous shrinkage due to the increasing use of high-performance concrete, which always contains supplementary materials. With the addition of supplementary materials—e.g., fly ash and blast furnace slag—internal relative humidity, chemical shrinkage and mechanical properties of cement paste will be affected. These properties significantly influence the autogenous shrinkage of cement paste. In this study, three supplementary materials—i.e., silica fume, fly ash and blast furnace slag—are investigated. Measurements of final setting time, internal relative humidity, chemical shrinkage, compressive strength and autogenous deformation of the cement pastes with and without supplementary materials are presented. Two water-binder ratios, 0.3 and 0.4, are considered. The effects of different supplementary materials on autogenous shrinkage of cement paste are discussed.

scholarly journals Properties of Calcium Sulfoaluminate Cement Mortar Modified by Hydroxyethyl Methyl Celluloses with Different Degrees of Substitution

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2136
Author(s):  
Shaokang Zhang ◽  
Ru Wang ◽  
Linglin Xu ◽  
Andreas Hecker ◽  
Horst-Michael Ludwig ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Cement Mortar ◽  
Retention Rate ◽  
Methyl Cellulose ◽  
Tensile Bond Strength ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Cement Mortars

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye’elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

Autoclaved Brick from Steel Slag and Silicon Tailings

2014 ◽  
Vol 878 ◽  
pp. 194-198 ◽  
Author(s):  
Peng Guan Li ◽  
Feng Qing Zhao
Keyword(s):  
Compressive Strength ◽  
Total Mass ◽  
Bending Strength ◽  
Steel Slag ◽  
Drying Shrinkage ◽  
Load Bearing ◽  
Volume Stability ◽  
Freeze Thaw

The load-bearing brick is made from steel slag and silicon tailings by pressing and autoclaving process. Because of the volume stability, steel slag was ground to above 320 m2/kg and wet cured in 50-60°C at 12-24 hours in the present of additives, before pressure forming and autoclaving process. Tailings account for 63% of the total mass of the brick, while steel slag 30 %. The compressive strength of the brick was up to 13.1MPa, bending strength 3.2MPa, and with low drying shrinkage and good freeze-thaw resistance. The application conditions were discussed.

scholarly journals INFLUENCE OF RELATIVE HUMIDITY ON COMPRESSIVE STRENGTH OF FLY ASH CEMENT PASTE

2008 ◽  
Vol 73 (631) ◽  
pp. 1433-1441 ◽  
Author(s):  
Warangkana SAENGSOY ◽  
Toyoharu NAWA ◽  
Pipat TERMKHAJORNKIT
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Relative Humidity ◽  
Cement Paste

scholarly journals Effect of Iron Phase on Calcination and Properties of Barium Calcium Sulfoaluminate Cement

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5813
Author(s):  
Jun Chang ◽  
Jixin Zhang ◽  
Yanchen Yuan ◽  
Kai Cui
Keyword(s):  
Compressive Strength ◽  
Liquid Phase ◽  
Eutectic Point ◽  
Material System ◽  
Phase Content ◽  
Calcium Sulfoaluminate Cement ◽  
Early Hydration ◽  
Calcium Sulfoaluminate ◽  
Eds Analysis ◽  
Iron Phase

In this paper, the effect of iron phase content on the calcination and properties of clinker and barium calcium sulfoaluminate cement was studied. The compressive strength of the samples was tested and combined with an XRD and SEM-EDS analysis, and the microstructure and composition of the barium calcium sulfoaluminate clinker and hydrated samples were characterized. The results showed that the oval-shaped particles were C2S minerals, and the hexagonal plate-shaped or rhombohedral dodecahedral particles were C2.75B1.25A3S¯. The Ba element was mainly distributed in the barium calcium sulfoaluminate region, and some of it was dissolved in C2S; the Fe element was distributed between C2.75B1.25A3S¯ and C2S crystal grains in the form of an iron phase solid solution, which acted as a solvent. When the iron phase composition was C4AF and the iron phase content was 5%, the early hydration and later strength were better, and the compressive strength after curing for 1, 3 and 28 days was 73.2 MPa, 97.9 MPa and 106.9 MPa, respectively. A proper amount of the iron phase can reduce the eutectic point of the sintered mature material system, increase the amount of liquid phase, reduce the viscosity of the liquid phase, effectively accelerate the migration of mineral ions and promote the formation and growth of minerals.

scholarly journals PROPERTIES OF CEMENT PASTE AND CONCRETE CONTAINING CALCIUM CARBIDE WASTE AS ADDITIVE

2016 ◽  
Vol 36 (1) ◽  
pp. 26-31
Author(s):  
EN Ogork ◽  
TS Ibrahim
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Calcium Carbide ◽  
Linear Shrinkage ◽  
Hardened Concrete ◽  
Concrete Compressive Strength ◽  
Initial Setting Time ◽  
Standard Procedures

This paper assessed the effect of calcium carbide waste (CCW) as additive on the properties of cement paste and concrete. The CCW used was sourced from a local panel beating workshop. It was sundried and sieved through a 75 µm sieve and characterized by X-Ray Fluorescence (XRF) analytical method. The consistency, setting times and drying linear shrinkage of cement paste with CCW addition of 0, 0.25, 0.5, 0.75 and 1.0 %, respectively by weight of cement were investigated in accordance with standard procedures. The slump values of fresh concrete containing CCW as additive and of 1:2:4 mix ratio and water-cement ratio of 0.5 was determined. A total of sixty numbers of 150 mm cubes of hardened concrete were tested for compressive strength at 1, 3, 7, 28 and 56 days of curing in accordance with standard procedures. The concrete compressive strength was also modeled using Minitab statistical software based on linear regression technique. The results of the investigations showed that CCW was predominantly of calcium oxide (95.69 %) and a combined SiO2, Al2O3 and Fe2O3 content of 3.14 %. The addition of CCW in cement decreased drying shrinkage (100 %), initial setting time (78 %) and final setting time (57 %), but increased consistency (14 %) at 1.0 % CCW content. The addition of CCW in concrete also showed slight increase in slump (6.5 %) and increase in compressive strength with increase in CCW additive up to 0.5 % and decrease in compressive strength with further increase in CCW content. The 28 days compressive strength of concrete with 0.5 % CCW content was 6.4 % more than normal, while that of concrete with 1.0 % CCW content was 14.9 % less than normal. The compressive strength model of CCW-concrete was developed with R2 value of 0.830 and could be used to predict concrete compressive strength. http://dx.doi.org/10.4314/njt.v36i1.4

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