Characteristics of Alkali-Activated Controlled Low-Strength Material Derived from Red Mud-Slag Blends

2017 ◽  
Vol 753 ◽  
pp. 343-348
Author(s):  
Chao Lung Hwang ◽  
Trong Phuoc Huynh
Keyword(s):  
Compressive Strength ◽  
Red Mud ◽  
Raw Materials ◽  
Setting Time ◽  
Public Works ◽  
Granulated Blast Furnace Slag ◽  
Naoh Solution ◽  
Strength Material ◽  
Low Strength ◽  
Alkali Activated

This investigation evaluates the characteristics of alkali-activated controlled low-strength materials (CLSM) that were produced using a mixture of red mud (RM) and ground granulated blast-furnace slag (GGBFS) with different RM-to-GGBFS weight ratios (100/0, 90/10, 80/20, and 70/30). A sodium hydroxide (NaOH) solution of 5M concentration was used as an activator. Characteristics of raw materials were checked carefully before using. The effects of GGBFS content on both fresh and hardened properties of the CLSM were evaluated through the tests of flowability, setting time, and compressive strength. Additionally, a scanning electron microscope (SEM) was used to examine the microstructural properties of the CLSM. Experimental results show that using more GGBFS in the mixture reduces flowability and increases the compressive strength of the CLSM. Moreover, the setting time of the fresh CLSM is associated positively with GGBFS content. Further, analysis of the optimal mixture was conducted basing on the test results. Thus, the properties of the CLSM sample containing 80% RM and 20% GGBFS conformed well to the requirements of the Public Works Department, Taipei Government, Taiwan. The results of this study further support the potential use of RM-GGBFS blends for the production of alkali-activated CLSM.

Thermal Conductivity of Controlled Low Strength Material (CLSM) Made Entirely from By-Products

2018 ◽  
Vol 773 ◽  
pp. 244-248
Author(s):  
Tan Manh Do ◽  
Young Sang Kim ◽  
Gyeong O Kang ◽  
My Quoc Dang ◽  
Thien Quoc Tran
Keyword(s):  
Thermal Conductivity ◽  
Red Mud ◽  
Setting Time ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Strength Material ◽  
Curing Condition ◽  
Low Strength ◽  
Controlled Low Strength Material ◽  
By Products

Various by-products generated from thermal power plants and chemical industries have considerably economic and environmental impacts in South Korea. This study focuses on evaluating thermal conductivity of controlled low strength material (CLSM) made entirely from by-products (e.g., coal ash, gypsum, red mud). In the experimental program, pond ash is used as a full replacement of natural sand whereas fly ash activated by a little lime, red mud, and gypsum is the main binder in the production of CLSM. Various laboratory tests including flowability, bleeding, initial setting time, and unconfined compressive strength were performed on the prepared CLSM mixtures to determine its general characteristics. Thermal conductivity is then measured subjected to saturated curing condition (SC) and room temperature curing condition (RTC). As a result, all general characteristics meet the specification of CLSM reported in ACI 229R by controlling the ratio of gypsum to red mud. In particular, the good flowability of higher than 20 cm is observed as the G/Rm ratio of smaller than 1.33. The bleeding values, ranging from 0.30% to 2.70%, fall into the bleeding requirement of CLSM of less than 5%. Moreover, the initial setting time and strength results are also in the acceptable specification of general CLSM in ACI 229R. Eventually, the thermal conductivity of the proposed CLSM was in the range of 0.84–0.87 (W/mK) and these values were considerably affected by the saturation states and curing conditions rather than binder proportion.

scholarly journals Optimizing Mixtures of Alkali Aluminosilicate Cement Based on Ternary By-Products

2021 ◽  
Vol 7 (7) ◽  
pp. 1264-1274
Author(s):  
Hoang Vinh Long
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Raw Material ◽  
Optimal Composition ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag ◽  
By Products

Portland cement is a popular binder but causes many adverse effects on the environment. That is due to the large consumption of raw materials and energy during production while emitting vast amounts of CO2. In recent years, Alkali Aluminosilicate Cement (AAC) has drawn much attention in research and development and promises to become a binder that can replace the traditional cement. In many studies of this binder, the content of the ingredients is often gradually changed to determine the optimal composition. The object of this paper is to optimize the composition of AAC using a combination of three by-products as the primary raw material, including Rush Husk Ash (RHA), Fly Ash (FA), and Ground Granulated Blast-Furnace Slag (GGBS). The investigation was conducted based on the critical parameter SiO2/Al2O3, and the D-optimal design. The FA and the GGBS were industrial product form, while the RHA was ground in a ball mill for 2 hours before mixing. The results show that this type of binder has setting time and soundness to meet standard cement requirements. While comparing to Portland cement, the AAC has a faster setting time, slower development of compressive strength in the early stages but a higher strength at the age of 56 days. According to the highest compressive strength at 28 days and high fly ash content, the optimal composition was RHA of 27.8%, FA of 41.8%, and GGBS of 15.4%, corresponding to the ratio SiO2/Al2O3 of 3.83. In addition, compressive strength at 28 days of the mortar specimens with the optimal binder and the ratio of water/ cement at 0.32 reached 63 MPa. Doi: 10.28991/cej-2021-03091724 Full Text: PDF

Engineering Properties of Controlled Low-Strength Material Made with Residual Soil and Class F Fly Ash

2014 ◽  
Vol 597 ◽  
pp. 345-348 ◽  
Author(s):  
Yeong Nain Sheen ◽  
Li Jeng Huang ◽  
Duc Hien Le
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Setting Time ◽  
Engineering Properties ◽  
Residual Soil ◽  
Strength Material ◽  
Low Strength ◽  
Controlled Low Strength Material ◽  
Class F Fly Ash

This paper aims to employ combination of residual soil and Class F fly ash in developing a controlled low-strength material (CLSM), primarily used as backfilling material. In the mixture, surplus soil and concrete sand was blended well together with a given proportion of 6:4 by volume. Three levels of binder content (i.e. 80-, 100-and 130 kg/m3) and different percentages fly ash (i.e., 0%, 15%, 30%, and 45%) substituting to Portland cement were previously chosen for mix design. Several major engineering properties of the CLSM such as fresh density, flowability, setting time, water bleeding, unconfined compressive strength, and elastic modulus were investigated via a laboratory study. Testing results indicate that most of the proposed CLSM mixtures satisfy the requirements of excavatability as the 28-days compressive strength ranges from 0.3 to 1.4 MPa. In addition, increase in FA substituting to OPC resulted in workability improvement, setting time extension as well as compressive strength and elastic modulus reduction.

scholarly journals Reuse of volcanic mud to controlled low-strength materials with cement and alkali-activated slag binders

2019 ◽  
Vol 107 ◽  
pp. 01008
Author(s):  
Chung-Ho Huang ◽  
Hao-Yu Fang
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Sodium Oxide ◽  
Engineering Properties ◽  
Fine Aggregate ◽  
Replacement Rate ◽  
Alkali Activated Slag ◽  
Low Strength ◽  
Activated Slag ◽  
Alkali Activated

This paper aims to evaluate the applicability of volcanic mud as the fine aggregate for controlled low-strength material (CLSM) by the experimental method. Two types of binder were selected, including cement and alkali-activated slag binders (without cement). The study mainly explored the effects of different addition rates of volcanic mud and different concentrations of alkaline agents (sodium hydroxide) on the engineering properties of CLSM. The test results show that the CLSMs with cement and volcanic mud have better workability and less water bleeding. However, the compressive strength of CLSM decreases as the replacement rate of volcanic mud increases, and the setting time also increases. The replacement rate of volcanic mud is recommended to be 20%. The volcanic mud mixed with the alkali-activated slag binder (without cement) can be successfully made into CLSM. When the concentration of sodium oxide in CLSM is 5%, although the compressive strength is highest at 7 days or 28 days, it cannot be hardened at the early age (before four days) and without compressive strength. CLSM with 20% sodium oxide concentration has poor workability. Its compressive strength is slightly lower than that of the 10% group. Therefore, the amount of calcium hydroxide recommended is 10%.

The Influence of the Properties of the Material Used for Obtaining Geopolymers on Their Structure and Compressive Strength

2017 ◽  
Vol 68 (6) ◽  
pp. 1182-1187
Author(s):  
Ilenuta Severin ◽  
Maria Vlad
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Wheat Straw ◽  
Red Mud ◽  
Blast Furnace Slag ◽  
Complex Structure ◽  
Point Of View ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag ◽  
Straw Ash

This article presents the influence of the properties of the materials in the geopolymeric mixture, ground granulated blast furnace slag (GGBFS) + wheat straw ash (WSA) + uncalcined red mud (RMu), and ground granulated blast furnace slag + wheat straw ash + calcined red mud (RMc), over the microstructure and mechanical properties of the synthesised geopolymers. The activation solutions used were a NaOH solution with 8M concentration, and a solution realised from 50%wt NaOH and 50%wt Na2SiO3. The samples were analysed: from the microstructural point of view through SEM microscopy; the chemical composition was determined through EDX analysis; and the compressive strength tests was done for samples tested at 7 and 28 days, respectively. The SEM micrographies of the geopolymers have highlighted a complex structure and an variable compressive strength. Compressive strength varied from 24 MPa in the case of the same recipe obtained from 70% of GGBFS + 25% WSA +5% RMu, alkaline activated with NaOH 8M (7 days testing) to 85 MPa in the case of the recipe but replacing RMu with RMc with calcined red mud, alkaline activated with the 50%wt NaOH and 50%wt Na2SiO3 solution (28 days testing). This variation in the sense of the rise in compressive strength can be attributed to the difference in reactivity of the materials used in the recipes, the curing period, the geopolymers structure, and the presence of a lower or higher rate of pores, as well as the alkalinity and the nature of the activation solutions used.

scholarly journals The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar

2021 ◽  
Vol 13 (4) ◽  
pp. 2407
Author(s):  
Guang-Zhu Zhang ◽  
Xiao-Yong Wang ◽  
Tae-Wan Kim ◽  
Jong-Yeon Lim ◽  
Yi Han
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Deionized Water ◽  
Internal Curing ◽  
Control Group ◽  
Alkali Activated Slag ◽  
Different Types ◽  
Naoh Solution ◽  
Activated Slag ◽  
Alkali Activated

This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.

Properties of lightweight alkali activated controlled Low-Strength material using calcium carbide residue – Fly ash mixture and containing EPS beads

2021 ◽  
Vol 297 ◽  
pp. 123769
Author(s):  
Saofee Dueramae ◽  
Sasipim Sanboonsiri ◽  
Tanvarat Suntadyon ◽  
Bhassakorn Aoudta ◽  
Weerachart Tangchirapat ◽  
...  
Keyword(s):  
Fly Ash ◽  
Calcium Carbide ◽  
Calcium Carbide Residue ◽  
Strength Material ◽  
Low Strength ◽  
Controlled Low Strength Material ◽  
Alkali Activated

scholarly journals Synthesis of Ambient Cured GGBFS Based Alkali Activated Binder Using a Sole Alkaline Activator: A Feasibility Study

2021 ◽  
Vol 11 (13) ◽  
pp. 5887
Author(s):  
Thandiwe Sithole ◽  
Nelson Tsotetsi ◽  
Tebogo Mashifana
Keyword(s):  
Silicate Solution ◽  
Environmental Footprint ◽  
Ambient Temperatures ◽  
Granulated Blast Furnace Slag ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Porous Morphology ◽  
Furnace Slag ◽  
Alkali Activated

Utilisation of industrial waste-based material to develop a novel binding material as an alternative to Ordinary Portland Cement (OPC) has attracted growing attention recently to reduce or eliminate the environmental footprint associated with OPC. This paper presents an experimental study on the synthesis and evaluation of alkali activated Ground granulated blast furnace slag (GGBFS) composite using a NaOH solution as an alkaline activator without addition of silicate solution. Different NaOH concentrations were used to produce varied GGBFS based alkali activated composites that were evaluated for Uncofined Compressive Strength (UCS), durability, leachability, and microstructural performance. Alkali activated GGBFS composite prepared with 15 M NaOH solution at 15% L/S ratio achieved a UCS of 61.43 MPa cured for 90 days at ambient temperatures. The microstructural results revealed the formation of zeolites, with dense and non-porous morphology. Alkali activated GGBFS based composites can be synthesized using a sole alkaline activator with potential to reduce CO2 emission. The metal leaching tests revealed that there are no potential environmental pollution threats posed by the synthesized alkali activated GGBFS composites for long-term use.

scholarly journals Alkali-Activated Zeolite 4A Granules—Characterization and Suitability Assessment for the Application of Adsorption

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 360
Author(s):  
Pauls P. Argalis ◽  
Laura Vitola ◽  
Diana Bajare ◽  
Kristine Vegere
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Morphological Properties ◽  
Solid Ratio ◽  
Suitability Assessment ◽  
Bet Analysis ◽  
Zeolite 4A ◽  
Compressive Strength Test ◽  
Alkali Activated

A major problem in the field of adsorbents is that binders (kaolin clay, bentonite) introduced to bind zeolites and ensure the needed mechanical strength, are not able to sorb gases like CO2 and N2, and decrease the overall adsorption capacity. To solve this problem, one of the pathways is to introduce a binder able to sorb such gases. Thus, in this study, the physical and mechanical properties of a novel binder based on metakaolin and its composite with zeolite 4A in the granular form were studied. Metakaolin was used as a precursor for alkali-activated binder, which was synthesized using an 8M NaOH activation solution. Raw materials were characterized using granulometry, X-ray diffraction (XRD), and differential thermal analysis (DTA); and final products were characterized using density measurements, a compressive strength test, XRD, Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM). Alkali-activated metakaolin was found to be efficient as a binding material when data for morphological properties were analyzed. A relationship was observed—by increasing the liquid-to-solid ratio (L/S), compressive strength decreased. Zeolite granule attrition was higher than expected: 2.42% and 4.55% for ZG-0.8, 3.64% and 5.76% for ZG-1.0, and 2.73% and 4.85% for ZG-1.2, measured at 4 and 5 atmospheres, respectively.

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