scholarly journals MICRO-MECHANICAL PROPERTIES OF CEMENT AND SLAG COMPOSITES MEASURED BY NANOINDENTATION

2020 ◽  
Vol 26 ◽  
pp. 45-49
Author(s):  
Jiří Němeček ◽  
Jiří Němeček
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Modulus Of Elasticity ◽  
Volume Fraction ◽  
Blended Cement ◽  
Hydration Products ◽  
Granulated Blast Furnace Slag ◽  
The Difference ◽  
Portland Cement Paste ◽  
Furnace Slag

In this study, the micromechanical response of two cementitious composites was characterized by nanoindentation. Pure Portland cement paste and Portland cement with 50 vol. % replaced with granulated blast furnace slag (GBFS) paste were investigated at the age of 28 days. Grid nanoindentation, statistical deconvolution and scanning electron microscopy were used to characterize the main hydration products. Several grids with approximately 500 indents on each sample were performed to obtain modulus of elasticity, hardness and creep indentation parameter. Similar mechanical phases containing calcium silica hydrate, crystalline calcium hydroxide and un-hydrated clinker were found in both samples varying by volume fraction. Blended cement, moreover, contains a phase of slag hydration products with a significantly lower modulus of elasticity. This phase with a high portion of unreacted GBFS is mostly responsible for the difference of mechanical properties of the whole composite.

Alkali Activation of Granulated Blast Furnace Slag

2010 ◽  
Vol 158 ◽  
pp. 1-11 ◽  
Author(s):  
Zi Qiao Jin ◽  
Xian Jun Lu ◽  
Shu Gang Hu
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Ordinary Portland Cement ◽  
Hydration Product ◽  
Early Age ◽  
Hydration Products ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

In order to stimulate the potential cementitious property of granulated blast furnace slag (GBFS), the ground GBFS sample (Wei Fang Iron and Steel Corporation, China) was activated by lime and gypsum under different dosages. The results showed that lime is an effective activator for the slag, and the optimum dosage of lime is about 10% (w/w) of the slag. At the optimum dosage of lime, the 28 days compressive strength of the lime-slag paste is higher than that of 32.5 ordinary Portland cement (OPC). But, the early age strength (3 and 7 days compressive strength) of the lime-slag paste is lower than that of the OPC. Addition of gypsum can effectively improve the early age strength of the lime-slag paste. At the ratio of gypsum:lime:slag of 8.2:9.2:82.6 (w/w), both the early and long-term compressive strengths of the gypsum-lime-slag paste are higher than that of the OPC. According to XRD, TG-DTA and SEM detections of the hydration products of the lime-slag paste, the gypsum-lime-slag paste and the OPC paste, it reveals that the hydration process of the GBFS-based cementitious material is different from the ordinary Portland cement and the presence of ettringite (AFt) contributes to the early age strength of the pastes. The major hydration product of the OPC paste (<7 days) were measured as ettringite (AFt), but the AFt phase was not detected in the hydration product of the lime-slag paste and the major hydration product of the lime-slag paste was determined as amorphous CSH gel. However, AFt was detected in the hydration products of the gypsum-lime-slag paste in the early stages of hydration, and the formation of AFt is favorable for the early strength improvement of the material.

scholarly journals Experimental Investigation of Material Properties and Self-Healing Ability in a Blended Cement Mortar with Blast Furnace Slag

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2564
Author(s):  
Seunghyun Na ◽  
Wenyan Zhang ◽  
Madoka Taniguchi ◽  
Nguyen Xuan Quy ◽  
Yukio Hama
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Blended Cement ◽  
Self Healing ◽  
Replacement Ratio ◽  
Dynamic Modulus Of Elasticity ◽  
Different Types ◽  
Furnace Slag

This paper presents the results of an experimental investigation on the material properties and self-healing ability of a blended cement mortar incorporating blast furnace slag (BFS). The effect of different types and Blaine fineness of BFS on the material properties and self-healing was investigated. Thirteen cement mixtures with BFS of different types and degrees of Blaine fineness are tested to evaluate the mechanical properties, namely compressive strength, bending strength, freeze–thaw, and accelerated carbonation. The pore structure is examined by means of mercury intrusion porosimetry. Seven blended mortar mixtures incorporating BFS for cement are used to evaluate the mechanical properties after applying freeze–thaw cycles until the relative dynamic modulus of elasticity reached 60%. The experimental results reveal that incorporating BFS improves the mechanical properties and self-healing ability. In the investigation of self-healing, smaller particle and high replacement ratios of BFS contribute to increasing the relative dynamic modulus of elasticity and decreasing the carbonation coefficient in the mortar after re-water curing. Moreover, BFS’s larger particles and high replacement ratio are found to provide better self-healing ability. A regression equation is created to predict the relative dynamic modulus of elasticity in mortar considering the Blaine fineness, BFS replacement ratio, and curing conditions.

scholarly journals Surface Characteristics of Portland Cement/Blast Furnace Slag Mixtures

1996 ◽  
Vol 13 (6) ◽  
pp. 461-467 ◽  
Author(s):  
Kh.A. Khalil
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Surface Characteristics ◽  
Hydration Products ◽  
Cement Pastes ◽  
Degree Of Hydration ◽  
Granulated Blast Furnace Slag ◽  
Granulated Slag ◽  
Furnace Slag

The effect of the degree of hydration and amounts of granulated blast furnace slag on the surface properties of Portland cement pastes were studied. The results obtained showed that the specific surface area SBET (m2/g) and pore volume Vp (cm3/g) decreased on increasing the degree of hydration. The addition of different amounts of granulated slag effected a decrease in SBET and Vp to an extent proportional to the amount present. These results were attributed to a replacement of clinker by the amounts of slag added and the formation of hydration products.

Mechanical properties and freezing and thawing durability of concrete incorporating a ground granulated blast-furnace slag

1989 ◽  
Vol 16 (2) ◽  
pp. 140-156 ◽  
Author(s):  
V. M. Malhotra
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Concrete Strength ◽  
Partial Replacement ◽  
Freezing And Thawing ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag ◽  
Durability Of Concrete

This paper gives the results of laboratory invstigations to determine the mechanical properties and freezing and thawing durability of concrete incorporating a granulated blast-furnace slag from a Canadian source. A series of fifteen 0.06 m3 concrete mixtures were made with water-to-(cement + slag) ratios (W/(C + S)) ranging from 0.70 to 0.45. The percentage of slag used as a partial replacement for normal portland cement ranged from 0 to 100% by weight. All mixtures were air entrained. A number of test cylinders and prisms were cast for determining the mechanical properties and freezing and thawing resistance of concrete.The test results indicate that the ground granulated blast-furnace slag can be used with advantage as a partial replacement for portland cement in concrete at 50% or lower replacement levels, especially at W/(C + S) of the order of 0.55 or lower. At 28 days, irrespective of the W/(C + S) and regardless of the percentage replacement of the cement by the slag investigated, the compressive strength of the concrete incorporating slag is comparable with that of the concrete made with normal portland cement. At all W/(C + S) and at all percentages of replacement, the flexural strength of the slag concrete is comparable with or greater than the corresponding strength of the control concrete. Durability of air-entrained slag concrete exposed to repeated cycles of freezing and thawing is satisfactory as evidenced by the high durability factors achieved. Key words: granulated slag, bleeding, time of setting, concrete, strength, freezing and thawing, shrinkage, creep, abrasion.

The Effect of Grinding Aids on Grinding Portland Cement with High Proportions of Slag

2012 ◽  
Vol 174-177 ◽  
pp. 191-197
Author(s):  
Su Zhen Sun ◽  
Yan Mei Yu
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Blast Furnace Slag ◽  
Blended Cement ◽  
Granulated Blast Furnace Slag ◽  
Grinding Aids ◽  
Furnace Slag

The paper brings information on grinding cement with high proportions of slag in the presence of amine alcohols grinding aids. Grind respectively blended cement with 20%, 50%, and 80% granulated blast furnace slag and analyse the evolution of the specific surface area at various grinding times and grindability. Results show that the specific surface area of belended cement depends on the content of slag and the type and ratio of grinding aid, and grindalility of the cement is also affected by grinding aids.

Performance of Blended Cement Concrete against Seawater Attack

2010 ◽  
Vol 64 ◽  
pp. 19-24
Author(s):  
H.H. Seleem ◽  
A.M. Rashad ◽  
B.A. El-Sabbagh
Keyword(s):  
Blended Cement ◽  
Strength Loss ◽  
Synthetic Seawater ◽  
Strength Deterioration ◽  
Ordinary Concrete ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mixtures ◽  
Concrete Permeability ◽  
Pozzolanic Materials ◽  
Furnace Slag

The current work reports the influence of synthetic seawater on some of the durability aspects of an ordinary concrete mixture (control) and six pozzolan-concrete mixtures. Three types of pozzolanic materials were employed; silica fume (SF), ground granulated blast furnace slag (GGBS) and metakaolin (MK). The pozzolanic materials were employed as an addition to cement in binary and ternary combinations. All mixtures were tested for strength deterioration ratio (SDR) after 3, 6, and 12 months of exposure to synthetic seawater, permeability was measured after 6 and 12 months of exposure. It was found through this investigation that pozzolans increase the ability of concrete to withstand aggressive environment and prevent most of the deterioration signs. The pozzolanic materials serve also to increase the strength and to minimize the strength loss (SDR) upon exposure to seawater. The pozzolanic materials led to reduce concrete permeability compared to control.

Research Progress on the Hydration of Portland Cement with Calcined Clay and Limestone

2021 ◽  
Vol 1036 ◽  
pp. 240-246
Author(s):  
Jin Tang ◽  
Su Hua Ma ◽  
Wei Feng Li ◽  
Hui Yang ◽  
Xiao Dong Shen
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Research Progress ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Early Hydration ◽  
Calcined Clay ◽  
Dense Microstructure

The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C3A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

Calorimetric determination of the effect of additives on cement hydration process

2013 ◽  
Vol 67 (2) ◽  
Author(s):  
Pavel Šiler ◽  
Josef Krátký ◽  
Iva Kolářová ◽  
Jaromír Havlica ◽  
Jiří Brandštetr
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Maximum Temperature ◽  
Granulated Blast Furnace Slag ◽  
Mineral Components ◽  
Maximum Temperatures ◽  
The Impact ◽  
Furnace Slag ◽  
Calorimetric Determination

AbstractPossibilities of a multicell isoperibolic-semiadiabatic calorimeter application for the measurement of hydration heat and maximum temperature reached in mixtures of various compositions during their setting and early stages of hardening are presented. Measurements were aimed to determine the impact of selected components’ content on the course of ordinary Portland cement (OPC) hydration. The following components were selected for the determination of the hydration behaviour in mixtures: very finely ground granulated blast furnace slag (GBFS), silica fume (microsilica, SF), finely ground quartz sand (FGQ), and calcined bauxite (CB). A commercial polycarboxylate type superplasticizer was also added to the selected mixtures. All maximum temperatures measured for selected mineral components were lower than that reached for cement. The maximum temperature increased with the decreasing amount of components in the mixture for all components except for silica fume. For all components, except for CB, the values of total released heat were higher than those for pure Portland cement samples.

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