Assessment of post-heat behavior of cement mortar incorporating silica fume and granulated blast-furnace slag

2020 ◽  
Vol 11 (2) ◽  
pp. 221-246
Author(s):  
Ghasem Pachideh ◽  
Majid Gholhaki

Purpose With respect to the studies conducted so far and lack of researches on the post-heat behavior of cement mortars containing pozzolanic materials, the purpose of this paper is to investigate the post-heat mechanical characteristics (i.e. compressive, tensile and flexural strength) of cement mortars containing granulated blast-furnace slag (GBFS) and silica fume (SF). In doing so, selected temperatures include 25, 100, 250, 500, 700 and 9000c. Last, the X-ray diffraction test was conducted to study the microstructure of mixtures and subsequently, the results were presented as power-one mathematical relations. Design/methodology/approach Totally, 378 specimens were built to conduct flexural, compressive and tensile strength tests. Accordingly, these specimens include cubic and prismatic specimens with dimensions of 5 × 5 × 5 cm and 16 × 4 × 4 cm, respectively, to conduct compressive and flexural strength tests together with briquette specimen used for tensile strength test in which cement was replaced by 7, 14 and 21 per cent of SF and GBFS. To study the effect of temperature, the specimens were heated. In this respect, they were heated with a rate of 5°C/min and exposed to temperatures of 25 (ordinary temperature), 100, 250, 500, 700 and 900°C. Findings On the basis of the results, the most profound effect of using GBFS and SF, respectively, takes place in low (up to 250°C) and high (500°C and greater degrees) temperatures. Quantitatively, the compressive, tensile and flexural strengths were enhanced by 73 and 180 per cent, 45 and 100 per cent, 106 and 112 per cent, respectively, in low and high temperatures. In addition, as the temperature elevates, the particles of specimens containing SF and GBFS shrink less in size compared to the reference specimen. Originality/value The specimens were cured according to ASTMC192 after 28 days placement in the water basin. First, in compliance with what has been specified by the mix design, the mortar, including pozzolanic materials and superplasticizer, was prepared and then, the sampling procedure was conducted on cubic specimens with dimension of 5 × 5 × 5 mm for compressive strength test, prismatic specimens with dimensions of 16 × 4 × 4 mm for flexural strength test and last, briquette specimens were provided to conduct tensile strength tests (for each temperature and every test, three specimens were built).

Author(s):  
Pratap Singh ◽  
Ramanuj Jaldhari

The aim of this study is to evaluate the performance of  M35 grade of concrete in addition of Ground-granulated blast-furnace slag and partial replacement of cement by glass fiber. Ground-granulated blast-furnace slag is pozzolanic materials that can be utilized to produce highly durable concrete composites. In this study Ground-granulated blast-furnace slag has been used to OPC which varies from 5% to 10% at interval of 2.5% by total weight of OPC and similarly partial replacement of OPC (43 grade) by glass fiber which varies from 0% to 0.4% at interval of 0.1% by total weight of OPC. All mixes (trial mix, control mix and variation mix) were prepared for M35 grade of concrete. This study investigates the performance of concrete mixture in terms of slump, compressive strength for 7days and 28 days, Flexural strength of beam 28 days and Splitting tensile strength of Cylinder for 28 days respectively.


2020 ◽  
Vol 323 ◽  
pp. 01018
Author(s):  
Wei-Ting Lin ◽  
Lukáš Fiala ◽  
An Cheng ◽  
Michaela Petříková

In this study, the different proportions of co-fired fly ash and ground granulated blast-furnace slag were used to fully replace the cement as non-cement blended materials in a fixed water-cement ratio. The recycled fine aggregates were replaced with natural fine aggregates as 10%, 20%, 30%, 40% and 50%. The flowability, compressive strength, water absorption and scanning electron microscope observations were used as the engineered indices by adding different proportions of recycled fine aggregates. The test results indicated that the fluidity cannot be measured normally due to the increase in the proportion of recycled fine aggregates due to its higher absorbability. In the compressive strength test, the compressive strength decreased accordingly as the recycled fine aggregates increased due to the interface structure and the performance of recycled aggregates. The fine aggregates and other blended materials had poor cementation properties, resulting in a tendency for their compressive strength to decrease. However, the compressive strength can be controlled above 35 MPa of the green non-cement blended materials containing 20% recycled aggregates.


2017 ◽  
Vol 7 (4) ◽  
pp. 413-425 ◽  
Author(s):  
Khalid Al-Gahtani ◽  
Ibrahim Alsulaihi ◽  
Mohamed Ali ◽  
Mohamed Marzouk

Purpose The purpose of this paper is to highlight the sustainability benefits of using demolition and industrial wastes as a replacement for aggregates and cement in traditional concrete mixes. Design/methodology/approach Crushed concrete from demolition sites served as a replacement for fine and coarse aggregate in some of the mixes at various ratios. In addition, ground granulated blast furnace slag, metakaolin, silica fume, and fly ash each served as a cement replacement for cement content in the mixes tested in this research at various rates. Compression strength tests, permeability, and thermal expansion tests were performed on various mixes to compare their performance to that of traditional mixes with natural aggregate, and with no cement replacement. Findings The compressive strength results indicated the suitability of using such demolition wastes as replacements in producing green concrete (GC) without hindering its mechanical characteristics significantly. In addition, the results indicated an enhancement in the mechanical characteristics of GC when replacing cement with pozzolanic industrial wastes and byproducts. Originality/value The research assesses the utilization of sustainable GC using recycled waste aggregate and byproducts.


2018 ◽  
Vol 230 ◽  
pp. 03016 ◽  
Author(s):  
Raisa Runova ◽  
Volodymyr Gots ◽  
Igor Rudenko ◽  
Oleksandr Konstantynovskyi ◽  
Oles’ Lastivka

Functionality of mortar and concrete mixes is regulated by surfactants, which act as plasticizers. The molecular structure of these admixtures can be changed during hydration of alkali-activated cements (AAC). The objective was to determine the chemical nature of plasticizers effective for property modification of mortars and concretes based on AACs with changing content of granulated blast furnace slag from 0 to 100 %. The admixtures without ester links become more effective than polyesters when content of alkaline component increase. The admixtures effective in high alkaline medium were used in dry mixes for anchoring (consistency of mortar 150 mm by Vicat cone; 1 d tensile strength in bending / compressive strength of mortar 6.6 /30.6 MPa) and in ready-mixed concretes (consistency class changed from S1 to S3, S4 with consistency safety during 60 min; 3 d compressive strength of modified concrete was not less than the reference one without admixtures).


2015 ◽  
Vol 802 ◽  
pp. 142-148
Author(s):  
M.N. Noor Azline ◽  
Farah Nora Aznieta Abd Aziz ◽  
Arafa Suleiman Juma

The article reports a laboratory experimental programme that investigated effect of ground granulated blast furnace (GGBS) on compressive strength of POFA ternary concrete. Compressive strength tests were performed at a range of cements combinations, including 100%PC, two POFA levels for binary concrete, 35% and 45%, and 15%GGBS inclusion for POFA ternary concrete. The compressive strength results were examined in comparison to PC only and equivalent POFA binary concretes for up to 28 days. Results show that the reduction in compressive strength is greater with the higher cement replacement level for all concretes particularly for POFA binary concretes. However, 15%GGBS in POFA blended concrete has a comparable compressive strength compared to PC concrete at both, 35% and 45%, cement replacement levels except for ternary concrete at 0.65 w/c. In addition, the compressive strength of ternary concrete is slightly higher compared to binary concrete for all concrete combinations. Although there is no significant noticeable influence on strength development, the presence of GGBS did not adverse the strength development of POFA blended concrete. Thus, it can be concluded that GGBS compensates the adverse effect of POFA at early strength development.


Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5190
Author(s):  
Laura Boquera ◽  
David Pons ◽  
Ana Inés Fernández ◽  
Luisa F. Cabeza

Six supplementary cementitious materials (SCMs) were identified to be incorporated in concrete exposed to high-temperature cycling conditions within the thermal energy storage literature. The selected SCMs are bauxite, chamotte, ground granulated blast furnace slag, iron silicate, silica fume, and steel slag. A microstructural characterization was carried out through an optical microscope, X-ray diffraction analysis, and FT-IR. Also, a pozzolanic test was performed to study the reaction of SCMs silico-aluminous components. The formation of calcium silica hydrate was observed in all SCMs pozzolanic test. Steel slag, iron silicate, and ground granulated blast furnace slag required further milling to enhance cement reaction. Moreover, the tensile strength of three fibers (polypropylene, steel, and glass fibers) was tested after exposure to an alkalinity environment at ambient temperature during one and three months. Results show an alkaline environment entails a tensile strength decrease in polypropylene and steel fibers, leading to corrosion in the later ones.


Author(s):  
Ashita Singh ◽  
Sudhir Singh Bhadauria ◽  
Manish Mudgal ◽  
Suresh Singh Kushwah

Use of Ordinary Portland cement contributes to environmental deterioration by releasing enormous quantity of CO2.To reduce use of cement, this research focuses on preparation of solely ground granulated blast furnace slag based geopolymer binder, activated by a combination of sodium hydroxide and sodium metasilicate cured under ambient temperature at 27°C. Engineering properties of geopolymer binder are evaluated and compared with conventional cement to assess its suitability as a binder for making geopolymer concrete. Compressive strength, flexure strength and split tensile strength are determined for geopolymer concrete. Microstructural analysis of geopolymer is performed by XRD, FTIR, FESEM and EDAX tests. The concentration of alkali activators is optimized by trials in laboratory and maximum compressive, flexural and split tensile strength of 44.07 MPa, 5.60 MPa and 4.39 MPa respectively, is obtained for geopolymer concrete at 2M concentration of sodium hydroxide solution with ratio of sodium metasilicate to sodium hydroxide taken as 2.0


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