Reactivity of Fine Quartz in Presence of Silica Fume and Slag

Arroudj, Karima; Zenati, Abdelfetah; Oudjit, Mohamed Nadjib; Bali, Abderrahim; Tagnit-Hamou, Arezki

doi:10.4236/eng.2011.36067

Cited by 13 publications

(5 citation statements)

References 12 publications

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“…At early age, the chemical activity of concrete mixes containing cementitious additions is mainly related to the hydration of the various minerals of the cement. Indeed at 20 °C, the pozzolanic activity of blast furnace slag remains very low for several days [15,16]. Heat flow peak is generally associated with the hydration of C3S, the main phase of Portland cement.…”

Section: Isothermal Calorimetrymentioning

confidence: 99%

Hydration, Shrinkages and Mechanical Properties of Ultra High Performance Concrete Containing Blast Furnace Slag and Algerian Dune Sand

Zenati

Tahlaiti

Khelidj

et al. 2019

JERA

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The new requirements for strength and durability have led to the development of Ultra High Performance concrete (UHPC) with outstanding mechanical properties and durability. However, the application of this type of concrete is exceptional, because of the high dosage of cement and the incorporation of expensive materials, such as silica fume (SF) whose dosage can reach 30% by weight of cement. This type of concrete is formulated on two bases: A fine granular skeleton (max diameter 630μm) and high cementitious materials content. The search for local materials to exploit them in the formulation of UHPC is the current trend. It is therefore necessary to control their effect on the behavior and evolution of cement hydration.The objective of this study is to highlight the influence of blast furnace (BFS) on hydration kinetics, linear endogenous shrinkage and chemical shrinkage at very early age (before 72h), drying shrinkage after hardening, as well as, the evolution of mechanical compressive strengths as a function of time. In addition, the exploitation of dune sand in the granular skeleton is an alternative to reduce the crushing energy and avoid microcracks possibly induced.The analysis of the results showed the interest of the use of the dune sand and the partial substitution of the cement by the BFS on the properties of the UHPCs in the fresh state and in the hardened state.In addition to the high performance achieved by UHPCs, their use, in Algeria, will meet both economic and ecological requirements given the abundance of very fine dune sand (southern Algeria) and complex blast furnace BFS of EL-Hadjar (Eastern Algeria).

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Section: Isothermal Calorimetrymentioning

confidence: 99%

Hydration, Shrinkages and Mechanical Properties of Ultra High Performance Concrete Containing Blast Furnace Slag and Algerian Dune Sand

Zenati

Tahlaiti

Khelidj

et al. 2019

JERA

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“…This reactivity is mainly due to the presence of amorphous fine particles adsorbed on crystalline particles. [16][17][18][19][20] This paper presents the results of an experimental program mainly based on the measurement of CH consumption by the SCMs, the setting time and water demand of modified blended pastes, and the compressive strength of mortars at 3 months. The results concern pastes and mortars in which different percentages of cement was replaced by ground PZ or SD.…”

Section: Research Significancementioning

confidence: 99%

“…This is in agreement with previous researches, the ground quartz or DS has a partial pozzolanic reactivity despite its crystalline structure. This is explained by the presence of amorphous thin particles of quartz adsorbed on crystalline particles [19,20].…”

Section: Thermal Analysis Tda/tgmentioning

confidence: 99%

Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials

Arroudj

Dorbani

Oudjit

et al. 2018

JERA

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Much of the current research on concrete engineering has been focused on including siliceous additions as supplementary cementitious materials (SCMs). Silica reacts with Calcium hydroxide release during cement hydration, and produces more C-S-H. The latter contributes to increase compactness, mechanical strengths and sustainability of concrete. This paper explores the hydration characteristics of cement paste based on various natural mineral additions, that are very abundant in Algeria and present a high silica content (ground natural pozzolana “PZ” and ground dune sand “DS”). For this purpose, several analyses were carried out on modified cement pastes and mortars. TheseSCMswere introduced by replacement levels of 15, 20 and 25 by weight of cement. We first, studied the effect of these SCMs on the heat of hydration and mechanical strength of mortars at different ages. The evolution of hydration of modified paste was studied, by using Thermal analysis (TG/TDA) at different ages, to analyze the Calcium Hydroxide (CH) content of the modified pastes. It is shown that the CH content of the mixes including SCMs is lower than that of the plain cement paste, indicating that silica reacts with the cement paste through a pozzolanic reaction. Increased pozzolanic activity results in higher amounts of Calcium Silicate Hydrate in the paste, which in turn results in higher compressive strength for modified cement mortars. Due to its crystalline morphology, the ground DS particles present a partial pozzolanic effect, compared to PZ which is semi-crystalline. Modified mortars by 20% DS can be the optimal composition. It presents satisfactory results: good mechanical strength and low heat of hydration. It can lead to an economic and sustainable concrete. Ground DS is very abounded in Africa and free of any impurities and can be a good alternativeSCMsin cement industry.

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“…Researchers [ 7 , 8 , 9 ] proved that sand in the desert can be used to make concrete mixtures without harmful effects. In addition, Arroudj et al [ 10 ] used desert sand for ultra-high-performance concrete and found that when desert sand was combined with the addition of amorphous morphology (blast slag or silica fume), it can compact the microstructure of concrete and improve the strength. According to the single factor test of Yang et al [ 11 ], the impact of desert sand replacement rate on the compressive strength of high-strength concrete showed a trend of first increasing and then decreasing.…”

Section: Introductionmentioning

confidence: 99%

Research on the Effect of Desert Sand on Pore Structure of Fiber Reinforced Mortar Based on X-CT Technology

Shi

Wang

et al. 2021

Materials

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Concrete is a multi-phase, porous system. The pore structure has an important influence on the properties of the concrete. In this paper, a kind of fiber reinforced mortar was prepared with desert sand and its pore structure was studied. The MIP technique was used to investigate the pore structure characteristics between 1 nm and 500 μm (in diameter). Meanwhile, the μX-CT technique was used to study the pore structure characteristics above 200 μm. It was found that the total porosity tends to decrease first and then increase as the dosage of desert sand increased. The porosity decreased gradually from the upper to bottom area inside the sample, and the diameter of the air voids near the upper area became larger. After curing for 28 days, the compressive strength of fiber reinforced mortar reached the maximum when the content of desert sand was 50%. In conclusion, the appropriate amount of desert sand can reduce the porosity of the fiber reinforced mortar to some extent and the number of large size air voids can be significantly reduced, which improves the pore structure and the mechanical properties of the fiber reinforced mortar.

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Reactivity of Fine Quartz in Presence of Silica Fume and Slag

Cited by 13 publications

References 12 publications

Hydration, Shrinkages and Mechanical Properties of Ultra High Performance Concrete Containing Blast Furnace Slag and Algerian Dune Sand

Hydration, Shrinkages and Mechanical Properties of Ultra High Performance Concrete Containing Blast Furnace Slag and Algerian Dune Sand

Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials

Research on the Effect of Desert Sand on Pore Structure of Fiber Reinforced Mortar Based on X-CT Technology

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