Novel Cementious Materials from Industrial Solid Waste for Silt Soil Solidification

2010 ◽  
Vol 150-151 ◽  
pp. 711-718
Author(s):  
Guo Hua Xie ◽  
He Qing Du ◽  
Shu Jing Zhu ◽  
Yong Jie Xue

Four kinds of industrial solid waste, granulated blast furnace slag (GBFS), electric furnace steel slag (EFSS), semi-dry flue gas desulfurization slag (FGDS) and gypsum were activated by mechanochemistry to prepare a novel kind of cementious material, DA type soil solidification agent (DA agent). Compared to the traditional cementious materials, this paper evaluated DA agent used in silt soil solidification project. Test results showed that DA-4 was prepared with adding the 40% CFBA, 39% GBFS, 11% OPC clinker and 10% gypsum by mill and more superior in material characteristics. It was found that compressive strength of DA-4 paste and mortar specimens at 28-days cured age were 46.0 and 27.3 MPa respectively; 5% of DA-4 was used to stabilize the silt soil in lab and the maximum dry unit weight, optimum moisture content, unconfined compressive strength and CBR value were 1.754 g/cm3, 15.35%, 1.15 MPa and 95.5% respectively. The hardening mechanism of prepared cementious materials is explained by two points: the sulfite or sulfate activation on alkali blast furnace slag; and the hydration product produced from cement clinker hydration process. Besides test programs of the trial pavement section in site showed that stabilized and solidified silt soils by DA-4 can meet the requirement of subgrade of pavement for strength and stiffness.

2017 ◽  
Vol 41 (19) ◽  
pp. 11299-11307 ◽  
Author(s):  
Rong Liu ◽  
Yifan Xu ◽  
Fei Ye ◽  
Feng Jia ◽  
Rui Xu

Mn–Ce based catalysts supported on Ti-bearing blast furnace slag (industrial solid waste) and the doping of transition metals were studied.


2010 ◽  
Vol 158 ◽  
pp. 1-11 ◽  
Author(s):  
Zi Qiao Jin ◽  
Xian Jun Lu ◽  
Shu Gang Hu

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.


2011 ◽  
Vol 287-290 ◽  
pp. 1275-1279
Author(s):  
Yong Jia He ◽  
Lin Nu Lu ◽  
Shu Guang Hu

Compound binding material was prepared by the alkali activation of metakaolin and ground granulated blast furnace slag. Hydration product components, microstructure and mechanical properties of the hardened paste were investigated by IR, XRD, SEM, MIP, and compressive strength measurement. Results indicated that hydration products included C-S-H and geopolymer, and both of them were amorphous although there were differences in their structure and morphology. When the dosage of slag was less than 50%, the compressive strength of hardened paste increased as the dosage increased, which was mainly because C-S-H produced by the reaction of GGBFS and alkali filled void in geopolymer phase, and part of unreacted slag particles acting as microaggregate to prevent from extension of microcrack in the hardened paste, so the porosity of hardened paste decreased and compressive strength increased.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5879
Author(s):  
Sung-Ho Bae ◽  
Jae-In Lee ◽  
Se-Jin Choi

Recently, interest in environmentally friendly development has increased worldwide, especially in the construction industry. In this study, blast furnace slag powder (BFSP) and mixed steel fine aggregates were applied to cement mortars to reduce the environmental damage caused by the extraction of natural aggregate and to increase the recycling rate of steel by-products in the construction industry. We investigated the fluidity, compressive strength, tensile strength, accelerated carbonation depth, and chloride ion penetration resistance of mortars with steel slag aggregate and their dependence on the presence or absence of BFSP. Because the recycling rate of ferronickel slag is low and causes environmental problems, we considered mortar samples with mixed fine aggregates containing blast furnace slag fine aggregate (BSA) and ferronickel slag fine aggregate (FSA). The results showed that the 7-day compressive strength of a sample containing both 25% BSA and 25% FSA was nearly 14.8% higher than that of the control sample. This trend is likely due to the high density and angular shape of steel slag particles. The 56-day compressive strength of the sample with BFSP and 50% FSA was approximately 64.9 MPa, which was higher than that of other samples with BFSP. In addition, the chloride ion penetrability test result indicates that the use of BFSP has a greater effect than the use of steel slag aggregate on the chloride ion penetration resistance of mortar. Thus, the substitute rate of steel slag as aggregate can be substantially enhanced if BFSP and steel slag aggregate are used in an appropriate combination.


2021 ◽  
Vol 11 (2) ◽  
pp. 830
Author(s):  
Katarzyna Konieczna ◽  
Karol Chilmon ◽  
Wioletta Jackiewicz-Rek

The main assumption of eco-efficient High-Performance Concrete (HPC) design is the reduction of Portland cement clinker content without negatively affecting the composite’s mechanical and durability properties. In this paper, three low-clinker HPC mixtures incorporating slag cement (CEM III/B as per EN 197-1) and Supplementary Cementitious Materials (SCMs)—Ground Granulated Blast Furnace Slag (GGBFS), Siliceous Fly Ash (SFA) and Silica Fume (SF)—were designed. The maximum amount of Portland cement clinker from CEM III/B varied from 64 to 116 kg in 1 m3 of concrete mix. The compressive strength of HPC at 2, 7, 14, 28, 56, 90 days, and 2 years after casting, as well as the modulus of elasticity on 2-year-old specimens, was tested. The depth of water penetration under pressure and internal frost resistance in freeze–thaw tests were evaluated after 56 days of curing. Additionally, the concrete pH value tests were performed. The microstructure of 2-year-old HPC specimens was analyzed using Scanning Electron Microscopy (SEM). The research proved that it is possible to obtain low-clinker High-Performance Concretes that reach compressive strength of 76–92 MPa after 28 days of curing, show high values of modulus of elasticity (49–52 GPa) as well as increased resistance to frost and water penetration under pressure.


2010 ◽  
Vol 168-170 ◽  
pp. 17-20
Author(s):  
Qiang Song ◽  
Bao Jing Shen ◽  
Zhi Jun Zhou

Under different content of blast furnace slag and steel slag powder, cements were mixed to investigate the effect of dosage of these two mineral admixtures on strength, autoclave expansion and the relationship between strength and volume fraction of pore. The results indicated that the ratio of clinker content to ground granulated blast furnace slag(GGBS) content is the crucial factor for compressive strength of mortars incorporated GGBS and steel slag at 28d. With different dosage of steel slag, the compressive strength of 1:1 mixes of clinker and GGBS has the maximum strength. With the steel slag mixed in cement, the porosity of cement pastes was increased. With the blast furnace slag mixed in cement, the porosity and pore size of cement pastes was decreased. Compressive strength of mortars was closely related to the content of pore in the sizes greater than 50 nm at 28d. Incorporating GGBS can significantly decrease the autoclave expansion of cement deduced by blending steel slag.


2020 ◽  
Vol 12 (14) ◽  
pp. 5783 ◽  
Author(s):  
Rosa Abnelia Rivera ◽  
Miguel Ángel Sanjuán ◽  
Domingo Alfonso Martín

Granulated blast-furnace slag (GBFS) and coal fly ash (CFA) are two well-known constituents in Portland cements. Ternary Portland cements (GBFS-CFA-K) provide environmental advantages by reducing Portland cement clinker (K) production and, therefore, promote lower CO2 emissions. Nevertheless, both of them cause a delay in the compressive strength gain. Given that, the early compressive strength for both constituents is low, but they improve the compressive strength at medium and later ages as consequence of the pozzolanic reaction. In this paper, a full factorial design with two levels was developed for the mortar compressive strength estimation at 2, 7 and 28 days. Mortar prisms made with 25% and 40% of granulated blast-furnace slag (GBFS) and/or coal fly ash (CFA) were tested. The effects of the interaction between GBFS and CFA on the compressive strength development of ternary Portland cement mortars were reported. Results show that the contribution of both cement constituents to the ternary mortar mix reduces the compressive strength for all the tested ages. Nevertheless, the finer the GBFS, the better ternary cement performance was achieved, showing that the synergistic effect is more effective when the finer GBFS is used, probably due to a more adequate particle size distribution. Finally, a relationship between compressive strength, fineness, GBFS content and CFA content was found for each age.


2012 ◽  
Vol 517 ◽  
pp. 611-616
Author(s):  
Javier Mazariegos Pablos ◽  
Eduvaldo Paulo Sichieri ◽  
Mário Sérgio de Andrade Zago

This research project accomplished a study on the technical feasibility of recycling industrial solid waste generated by the discharge of casting sand agglomeration with clay and blast furnace slag. For this, the plan proposed a methodology that initially establishes a process of solid waste encapsulation, by using solidification/stabilization technique on Portland cement matrices, in which the residuals act as small and large aggregates on the composition of concrete, and later it presents the possibility of using this concrete in the manufacture of concrete pieces (concrete blocks) for paving. The results obtained in this research achieved the objective set with great success, regarding the manufacturing of concrete pieces (blocks) for paving urban roads, whenever there is special vehicle traffic or demands capable of producing accentuated abrasion effects (surpassing the 50 MPa required by the regulation), which probes the technical practicability of using waste from sand casting agglomeration with clay and blast furnace slag used in this study, unlocking usage possibilities for construction.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Bong-Suk Cho ◽  
Kyung-Mo Koo ◽  
Se-Jin Choi

This study investigates the effect of desulfurization slag (DS) and gypsum (G) on the compressive strength and microstructure properties of blast furnace slag-(BFS-) based alkali-activated systems. DS is produced in a Kambara reactor process of molten iron produced in a steel production process. DS contains CaO, SiO2, Fe2O3, and SO3 and is composed of Ca(OH)2 and 2CaO·SiO2 as main compounds. In this investigation, the weight of BFS was replaced by DS at 5, 10, 15, 20, 25, and 30%. In addition, G was also applied at 9, 12, and 15% by weight of BFS to improve the compressive strength of the alkali-activated system with BFS and DS. According to this investigation, the compressive strength of the alkali-activated mixes with BFS and DS ranged from 14.9 MPa (B95D5) to 19.8 MPa (B90D10) after 91 days. However, the 28 days compressive strength of the alkali-activated mixes with BFS, DS, and G reached 39.1 MPa, 45.2 MPa, and 48.4 MPa, respectively, which were approximately 78.8 to 97.5% of that of O100 mix (49.6 MPa). The main hydrates of the BFS-DS (B80D20) binder sample were Ca(OH)2, CaCO3, and low-crystalline calcium silicate hydrates, while the main hydration product of BFS-DS-G (B75D10G15) binder was found as ettringite. The use of BFS-DS-G binders would result in the value-added utilization of steel slag and provide an environmentally friendly construction material, and contribute to a reduction of CO2 in the cement industry.


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