scholarly journals A new expansion material used for roof-contacted filling based on smelting slag

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hua Na ◽  
Guocheng Lv ◽  
Lijuan Wang ◽  
Libing Liao ◽  
Dan Zhang ◽  
...  

AbstractThe improper handling of smelting slag will seriously pollute the environment, and the unfilled roof of the goaf of the mine will threaten the safety of the mine. Expansion materials have attracted more and more attention because of their excellent properties. In this paper, copper-nickel smelting slag that has some active ingredients of gelling is used instead of traditional aggregate and some part of cement in order to reduce its pollution to the environment and its costs. For safety reasons, hydrogen peroxide was chosen as the foaming agent. Sodium silicate and hexadecyl trimethyl ammonium bromide (CTAB) are used as additives. Our results showed that after 28 days of curing, the material has better mechanical properties and the early compressive strength of the material was enhanced by sodium silicate. The efficiency of foaming was improved by CTAB. It also proves that copper–nickel smelting slag can be used in expansion material. At the same time, the utilization rate of the copper–nickel smelting slag of this formula can reach 70%, reduce its pollution to the environment.

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 523-540
Author(s):  
Imed Beghoura ◽  
Joao Castro-Gomes

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 w.% to 0.05 w.% of precursor weight. Expanded granulated cork (EGC) particles were incorporated (10% to 40% of the total volume of precursors). The physical and mechanical properties of the foamed materials obtained, the effects of the amount of the foaming agent and the percentage of cork particles added varying from 10 vol.% to 40% are presented and discussed. Highly porous structures were obtained, Pore size and cork particles distribution are critical parameters in determining the density and strength of the foams. The compressive strength results with different densities of AA-LFM obtained by modifying the foaming agent and cork particles are also presented and discussed. Mechanical properties of the cured structure are adequate for lightweight prefabricated building elements and components.


2019 ◽  
Vol 274 ◽  
pp. 03002
Author(s):  
Imed Beghoura ◽  
Joao Castro-Gomes ◽  
Haroon Ihsan ◽  
John Pickstone ◽  
Nuno Estrada

Several mixes of alkali activated foams from tungsten mud waste (MW), grounded glass (GG) and metakaolin (MK) were developed incorporating expanded granulated cork (EGC). This study presents preliminary results of the expansion process obtained with the addition of aluminium (AL) powder as a foaming agent. 0.3 wt.%, 0.4 wt.% to 0.5wt.% of AL powder were added to the alkali activated matrix. The physical and mechanical properties of the obtained foams, the effects of the type and amount of the foaming agent added are presented and discussed. Highly porous structures were obtained, with overall expansion up to 68.2% when the AL powder was added. The size and distribution of pores are shown. The compressive strength of foams in the case of highly porous structures achieved of 1.2 MPa for the samples containing 0.5 wt.% of AL powder. Mechanical and thermal properties of the cured structure are good and can therefore be used for applications in acoustic panels and lightweight prefabricated components for thermal insulation purposes.


2013 ◽  
Vol 795 ◽  
pp. 664-668 ◽  
Author(s):  
Roshasmawi Abdul Wahab ◽  
Mohd Noor Mazlee ◽  
Shamsul Baharin Jamaludin ◽  
Khairul Nizar Ismail

In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.


Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 303 ◽  
Author(s):  
Lijuan Wang ◽  
Yanke Wei ◽  
Guocheng Lv ◽  
Libing Liao ◽  
Dan Zhang

Gellable composite materials (GCM) were prepared from a smelting slag of copper and nickel deposits and cement, and activated using gypsum and chemical activators. The effects of material ratio, dosage of chemical activators, and gypsum on the mechanical properties of GCM were studied. Our results showed that the chemical activators of Na2SO4, Na2SiO3, NaOH, and Na2CO3 could improve the compressive strength of the GCM. Considering the market cost and ease operation, the compressive strength of the GCM could be significantly improved with 2% Na2SO4. The experiment results also showed that the compound chemical activator could improve the compressive strength of gelled material. The strength of GCM reaches 41.6 MPa when 2% gypsum and 80% of smelting slags of copper and nickel deposits were used, which met the national standards requirements of GCM. As such, it is expected that a large amount of copper and nickel mining smelting slag could be utilized for the production of cementitious materials.


2018 ◽  
Vol 163 ◽  
pp. 06003
Author(s):  
Tomasz Piotrowski ◽  
Piotr Prochoń

The development of sustainable building materials with reduced environmental footprint in both, manufacturing and operational phases of the material lifecycle, is attracting increased interest in the construction industry worldwide. A recent innovation, the geopolymer foam concrete, combines the performance benefits and operational energy savings achievable through the use of lightweight foam concrete, with the cradle-togate emissions reductions obtained through the use of a geopolymer binder derived from granulated blast-furnace slag (GBFS). In this study mechanical properties of GBFS-based foam concrete were investigated for samples of different water to solid ratio (0.252, 0.287 and 0.321). According to ASTM C 796-97 both mass of the foaming solution and water in sodium silicate solution was considered as part of the total amount of mixing water. As a solid part, GBFS and solid part of activators (NaOH and sodium silicate) was accounted. A group of specimens (40x40x160 beams and 100x100x100 cubes) have been prepared and volume density, bending, compressive strength tests have been performed. In a result an optimized lightweight GBFS-based geopolymer foam concrete was obtained, characterized by 1.8 kg/dm3 volume density, 2.6 MPa bending strength and 51.8 MPa compressive strength measured on beams and 44.1 MPa compressive strength on cubes.


2013 ◽  
Vol 594-595 ◽  
pp. 8-12 ◽  
Author(s):  
Y. Zarina ◽  
Hussin Kamarudin ◽  
Abdullah Mohd Mustafa Al Bakri ◽  
I. Khairul Nizar ◽  
A.R. Rafiza

The waste material from palm oil industry has been increasing since Malaysia was the world largest exported of palm oil mill. The waste such as palm fibers, nut shells, palm kernel and empty fruit bunches are the solid waste the obtained from palm oil processing for oil extraction. When these wastes were incinerated, the waste from the burning process known as boiler ash was obtained at the lower compartment of the boiler. The production of boiler ash was estimated to be over 4 million tones/ year. This paper investigates the influence of dolomite on the mechanical properties of boiler ash based geopolymer pastes. The boiler ash was calcined at 800oC for 1 hour. After that, the dolomite was replaced in boiler ash at 1, 2, 3, 4 and 5% wt where the geopolymer samples were cured 80 oC. Sodium silicate and sodium hydroxide (NaOH) with concentration 12 Molar has been used as alkaline activator to synthesis the boiler ash to produce geopolymer paste. The ratio of solid/liquid and sodium silicate/NaOH was 1 and 2.5 for all geopolymer paste. The result showed the addition of dolomite has decrease the strength of boiler ash based geopolymer. The geopolymer sample without addition of dolomite showed the maximum compressive strength (19.4 MPa) at 28 days testing. Meanwhile the addition of 4% of dolomite into geopolymer paste has the maximum compressive strength (7.3 MPa) compared to others. Additions of dolomite into boiler ash based geopolymer have reduced the compressive strength at 28 days of testing.


2021 ◽  
Author(s):  
Davoud Khademi ◽  
Elahe Khodeir ◽  
Seyed Mostafa Mahdizadeh ◽  
Hamideh Yari

Abstract Physical properties and processing parameters of the reinforcing phase such as shape and content can dramatically influence the mechanical properties of the composites. In this project, the effect of different shapes of silicon dioxide or silica (SiO2) reinforcement including nanoparticle and nanotube as well as their weight percent (1, 3, 5 and 10 wt %) on the mechanical properties of aluminum (Al) composite were investigated. The silica nanotubes (SNTs) were prepared by hydrothermal methods. In order to achieve a good dispersion, Al powders were coated by cetyl trimethyl ammonium bromide (CTAB) to obtain a surface positive charge. Then, SiO2–Al powders were obtained by electrostatic self-assembly to realize the homogeneous adsorption of SiO2 nano reinforcement on Al powders. Finally, SiO2-reinforced Al matrix composites were fabricated by powder metallurgy. Characterization of composites was carried out by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). For determination of the mechanical properties of the composite, the compressive strength and density were investigated.Results showed a significant reduction in the relative density from 98% to 84% for composites containing 0 to 10 wt % of SiO2. The compressive strength exhibited a moderate increase by adding SNTs while in samples containing SiO2 nanoparticles, the mechanical properties improved and reached a peak value of 225 MPa at 5 wt % SiO2 nanoparticles (~40% increase compared to pure Al). However, a further increase in nanotubes content resulted in a considerable reduction in compressive strength. This can be attributed to the increase in porosity and agglomeration of nano reinforcement in the composite.


2014 ◽  
Vol 488-489 ◽  
pp. 94-97
Author(s):  
Long Wu ◽  
Yi Hong Zhao ◽  
Rong Fa Chen ◽  
Hua Yang ◽  
Qing Qing Li ◽  
...  

The MnO2 was used as foaming agent to produce the glass foams in this paper. The macro morphology, physical properties and the metallurgical structure were discussed in detail by the modern means of DTA, SEM and XRD analysis. The results indicated that the less dense and more uniform pore size of foam glass was prepared, and the good mechanical properties were obtained. And the main crystal was quartz, nepheline and albite by the XRD method.


2018 ◽  
Vol 7 (3.10) ◽  
pp. 66
Author(s):  
T Subramani ◽  
R Amul

Foam concrete is a form of aerated lightweight concrete. Foamed concrete has emerged as most industrial fabric in Production Company. Foam concrete is produced while pre-fashioned foam is brought to slurry, the characteristic of froth is to create an air voids in cement–primarily based absolutely slurry. Foam is generated one by one via using foam generator; the foaming agent is diluted with water and aerated to create the froth. The cement paste or slurry set throughout the foam bubbles and whilst the froth being to degenerate, the paste has enough power to keep its form around the air voids. Consequently, this study investigates bodily and mechanical residences of foamed concrete. Ultimately comparative analyses had been finished to decide the relationships the various numerous mechanical homes parameters of the foamed concrete, especially the compressive strength, flexural electricity, splitting tensile electricity. The specimen analysed by means of the usage of the use of e- tab software program.  


2018 ◽  
Vol 281 ◽  
pp. 175-181
Author(s):  
Hui Teng Ng ◽  
Cheng Yong Heah ◽  
Yun Ming Liew ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin

In the present work, a comparative study of the thermal performance of unfoamed and foamed geopolymers was investigated. The geopolymers were prepared by mixing fly ash with alkali activator (a mixture of sodium hydroxide and sodium silicate). The geopolymer foams were prepared by adding hydrogen peroxide (H2O2, 2wt.% and 4wt.%). The geopolymers were cured at room temperature (29°C) for 24 hours and at 60°C for another 24 hours. The bulk density and compressive strength decreased with increasing H2O2 up to 2wt.% and increased when 4wt.% of H2O2 was added. In order to test the thermal resistance, the geopolymers were heated at elevated temperature (200- 1000°C). Unheated geopolymers showed bulk density and compressive strength in the range of 1.6– 1.7g/cm3 and 15–17MPa, respectively. When heated up to 1000°C, the geopolymers could withstand high temperature without any disintegration and spalling. Both unfoamed and foamed geopolymers showed highest compressive strength at 200°C (17–22MPa). Further decreased in compressive strength was observed upon heating up to 800°C (10–17MPa). The compressive strength regained (14–21MPa) when heated up to 1000°C. The compressive strength was even higher than that recorded at room temperature. In the present work, unfoamed geopolymers showed overall higher thermal resistance than foamed geopolymers.


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