Blast Furnace Slag Cement Research Articles

A Study on the Shrinkage Cracking Properties of Concrete by Using Blast Furnace Slag Cement and Frost-Resistant Accelerator

A Study on the Shrinkage Cracking Properties of Concrete by Using Blast Furnace Slag Cement and Frost-Resistant Accelerator

Study on the characteristics of grout material using ground granulated blast furnace slag and carbon fiber

This study aims to evaluate the applicability of a grout material that is mixed with carbon fiber, biogrout, ground granulated blast furnace slag (GGBS) powder and cement. Uniaxial compressive strength tests were performed on homo-gel samples at days of 1, 3, 7, 14 and 28. In addition, the variation of permeability with the mixing ratios was measured. Based on the uniaxial compressive strength test, it was confirmed that the uniaxial compressive strength increased by 1.2times when carbon fiber increased by 1%. In addition, as a result of the permeability test, it was found that when the GGBS increased by 20%, the permeability coefficient decreased by about 1.5times. Therefore, the developed grout material can be used as a cutoff grouting material in the field due to its strength and cut-off effect.

A Study on the Long-term Durability of High-Volume Ground Granulate Blast Furnace Slag Cement Concrete for 41years

A Study on the Long-term Durability of High-Volume Ground Granulate Blast Furnace Slag Cement Concrete for 41years

Property of Low Heat and Shrinkage Type Blast-Furnace Slag Cement and Case of Construction

Property of Low Heat and Shrinkage Type Blast-Furnace Slag Cement and Case of Construction

Efficiency of wet-grinding on the mechano-chemical activation of granulated blast furnace slag (GBFS)

This work aims at evaluating the effect of wet grinding on the properties of blast furnace slag (BFS) and the properties of BFS-cement mixtures. Different grinding time are considered from 10 min to 50 min at intervals of 10 min. The morphology and structure properties of ground BFS and the physical properties of BFS slurries as the function of grinding duration are analyzed. BFS cement pastes with wet-grinding BFS content of 50% are characterized. Setting time, mechanical property, microstructure and hydration products analyses are performed to evaluate the performance of wet-grinding BFS. The results indicate that wet grinding is an effective method to treat BFS, which can decrease the average particle size to 2.95 μm after 50 min of grinding, but no significant influence on the bulk minimum particle size. Wet grinding not only gives rise to a transition of zeta potential value from minus to plus, but also cause the value to increase constantly with the treatment duration. Mixtures containing wet grinding BFS present high reactivity according to the shortening of setting time, improvement of mechanical strength and reduction of porosity and Ca(OH)2.

Analysis of the Properties of Expansive Concrete With Portland and Blast Furnace Cement

AbstractThe properties of expansive concretes made of two types of cement: Portland cement CEM I and blast furnace slag cement CEM III were tested. The expansion of the concrete was caused by using an expansive admixture containing aluminium powder added in an amount of 0.5; 1 and 1.5% of cement mass. It was found that the compressive strength of concrete with CEM I decreased after using an expansive admixture in the amount of more than 0.5% of the cement mass. The compressive strength of concrete with CEM III decrease after addition of admixture in the entire range of dosages used. On the basis of electrochemical measurements, it was found no influence of an expansive admixture on corrosion of reinforcing steel. The use of an expansive admixture causes a slight increase in the effective diffusion coefficient of chloride ions in concrete.

Prevention of bleeding of particulate grouts using biopolymers

The potential applicability of several biopolymers, including xanthan gum, diutan gum, acacia gum, modified starch, guar gum and a cellulosic polymer, for maintaining the solid particles of a particulate grout in suspension has been evaluated through static bleeding tests. The grout material investigated was ground granulated blast-furnace slag (GGBS) cement prepared at different water to binder ratio values ranging from 2:1 to 5:1. Among the biopolymers studied, diutan gum and xanthan gum were found to have the highest performance in bleeding prevention at very low concentrations in ranging 0.25–1.0%. A synergy was observed for xanthan gum and guar gum and for xanthan gum and cellulosic polymer combinations. This helps reduce the overall amount of biopolymer required for suspension stabilization. By measuring the zeta potential and viscosity values of the biopolymer-added grouts, the mechanisms underlying the sedimentation inhibitory action of the biopolymers are discussed.

Microstructure and composition of fly ash and ground granulated blast furnace slag cement pastes in 42-month cured samples

Microstructure and composition of 42-month cured pastes using Portland cement (OPC), fly-ash cement (FAC), and ground-granulated-blast-furnace-slag cement (GGBFSC) were investigated. The granular structure of C-A-S-H in outer products of GGBFSC and FAC pastes was finer than in OPC paste. Fly ash offered higher capacity in increasing the Si/Ca ratio of C-A-S-H than slag in the pastes. However, their effects on the chain length were opposite. The incorporation of aluminum into silicate anions in GGBFSC paste was greater compared to others. AlO45− played an essential role in bridging the shorter silicate anions together, forming a longer chain of aluminosilicate anions in the pastes. Mg-Al layered-double hydroxide (LDH) was abundant in the inner products of slag particles with the interbedding of TAH, leading to a low ratio of Mg/Al ratio on hydrotalcite-like phase.

Experimental Study for Effects of Hydrate Products on Shrinkage Behaviour in Low Volume Blast Furnace Slag Cement Concrete

Blast furnace slag (BFS) cement concrete is reported to be prone to shrinkage cracking at high temperature in tropical climate. To solve this problem is important to extend BFS cement concrete which is known as a key to reduce carbon footprint in concrete production. This study focuses shrinkage reducing effects to increase gypsum and calcium carbonate in low volume BSF cement concrete as trace additives. Free shrinkage experiment and hydration analysis experiment are conducted to clarify the focused issues. These two experiments clarified that: i) increasing gypsum amount up to 4.5% of binder mass effectively reduced free shrinkage strain subjected to 30 degree of ambient temperature, ii) this free shrinkage reduction is considered due to restraining transformation of Ettringite to Monosulfate, which is known to lead serious volume reduction in hydrate products, iii) increased gypsum amount up to 4.5% appeared not a source of Delayed Ettringite Formation.

The effect of ultrahigh volume ultrafine blast furnace slag on the properties of cement pastes

The dosage of blast furnace slag (BFS) in cement is limited on account of relative low reaction rate and low early strength. Improving the early age activity of BFS is the fundamental solution for high volume BFS cementitious materials. Generally, mechanical activation is one of the main techniques to accelerate the early reaction of mineral admixtures. In this study, wet-milling and dry-separation are respectively used to prepare ultrafine BFS to improve its early reactivity. The early hydration characteristics, mechanical property, hydration products of ultrahigh volume BFS cementitious materials are analyzed to assess the efficiency of ultrafine BFS on the properties of BFS cement paste. The results show that the initial and final setting time both gradually decrease as the dry-separation BFS (GS) dosage increases, while the wet-milling BFS (WS) series present the opposite tendency. The electrical resistivity of WS specimens develops at a faster rate than that of GS specimens. Mixes containing WS, at a maximum dosage of 90%, have higher mechanical property than those with GS, resulting in an enhancement of strength. The hydration products mainly include calcium hydroxide, hydrotalcite, hydrotalcite-like phase, calcium carbonate, strätlingite, C-S-H, C-A-S-H, and akermanite.

Phase evolution of slag-rich cementitious grouts for immobilisation of nuclear wastes

An updated calcium silicate hydrate (C–S–H) model incorporating aluminium-containing end-members was used for thermodynamic modelling of blended cements using blast-furnace slag and Portland cement (BFS:PC) with ratios of 1:1, 3:1 and 9:1, using GEMSelektor. Selective dissolution and magic angle spinning nuclear magnetic resonance (MAS NMR) studies were performed to determine the degree of hydration (DoH) of the anhydrous material as an input parameter for the modelling work. Both techniques showed similar results for determining the DoH of the BFS within each sample. Characterisation of the hardened cement pastes over 360 days, using X-ray diffraction analysis and MAS NMR, demonstrated that the use of the updated C–S–H model can highlight the effect of different blend ratios and curing ages on the phase assemblages in these cements. Validation using this modelling approach was performed on 20 year old specimens from the literature to highlight its applicability for modelling later-age blended cements.

Fresh and hardened properties of self-compacting concrete with sugarcane bagasse ash–slag blended cement

This study focuses on combined usage of agro and industrial wastes in developing environment-friendly concrete. Fresh and hardened characteristics of self-compacting concrete (SCC) made of blended cement with sugarcane bagasse ash (SBA, an agro-waste generated during sugar manufacture), granulated blast furnace slag (BFS) and Ordinary Portland cement were examined through an experimental program. Three SCC mix groups (BA10, BA20, and BA30) corresponded with three cement replacing levels of SBA (10%, 20%, and 30%) were developed. For each group, four mixtures associated with four replacement ratios of cement by slag were further employed (0%, 10%, 20%, and 30%). Totally, 12 mixtures incorporating SBA and BFS blended-cement and one reference mix were developed for experiment. Fresh properties of the proposed SCC were evaluated through measurement of the density, slump, slump-flow, V-funnel test, T500 slump, Box-test, and setting time. In addition, testing of compressive strength, ultrasonic pulse velocity, sulfate attack, water absorption as well as electrical resistivity were conducted for hardened concrete. The testing results indicated that replacing either SBA and/or BFS to OPC in mixtures led to lesser flowability. Compressive strength of sample made of 30% SBA and 30% BFS substituting to OPC were comparable to that of control after 91 days. Moreover, both of SBA and BFS strongly enhanced sulfate attack resistance; and almost SCC samples had a negligible corrosion rate after 28-day ages.

Review of the Heavy Metals in Blast-furnace Slag Cement

Review of the Heavy Metals in Blast-furnace Slag Cement

Changes in Heavy Metal Content of Blast Furnace Slag Cement According to Blast Furnace Slag Content

Changes in Heavy Metal Content of Blast Furnace Slag Cement According to Blast Furnace Slag Content

Low-carbon and low-alkalinity stabilization/solidification of high-Pb contaminated soil

Stabilization/solidification (S/S) is a low-cost and time-efficient method for soil remediation, however, delayed hydration reactions and high carbon footprint are major limitations for the treatment of high-Pb contaminated soil. This study develops a novel and low-carbon approach that combines ground granulated blast furnace slag (GGBS) and ordinary Portland cement (PC) with phosphate-/sulphate-rich byproducts to produce low-alkalinity, high-compatibility, high-strength binary cement (BC) for S/S process. Results show that contaminated soil with a large fraction of exchangeable and soluble Pb (e.g., shooting range sites) severely disturbed the formation of hydration products in conventional S/S treatment, whereas BC system could mitigate the Pb interference via precipitation and sorption evenly distributed on the BC hydrates as shown by elemental mapping. Thus, BC presented superior environmental performance in terms of toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching tests, which were substantiated by quantitative X-ray diffraction and thermogravimetric analyses. The addition of potassium dihydrogen phosphate reduced TCLP leachability of Pb by 86.9% and Pb diffusion coefficients by 69.4% due to the formation of insoluble Pb3(PO4)2. Similarly, incinerated sewage sludge ash enhanced Pb stabilization, whereas waste phosphogypsum increased early strength via precipitation of PbSO4, although the effectiveness of physical encapsulation was compromised due to reduction in hydration products. Therefore, the proposed binary binders with selected additives present a new and low-carbon S/S treatment for high-Pb shooting range soil remediation.

Alkali-activated Portland blast furnace slag cement mortars: Performance to alkali-aggregate reaction

This report evaluates the performance to alkali-aggregate reaction of two types of binder systems: a Portland blended cement and an Alkali-activated Portland blended cement. The first system consists of 80% granulated blast furnace slag and 20% Portland cement (OPC) and was hydrated in the presence of water (CE), whereas the second incorporated an alkaline activator, making it a hybrid cement (HB). Expansion measurements of mortar bars were carried out, and their behaviour was compared to a reference system based on 100% OPC. Additionally, a microstructural characterization was performed using scanning electron microscopy. The results show that CE and HB cements had smaller expansions than OPC, although Rosette and pseudo-Rosette structures were observed.

Engineering Characteristics of Geopolymer Mortars Manufactured with Ground Granulated Blast Furnace Slag

Geopolymers are obtained by various methods in different alkaline environments by changing compositions and crystal structures of pozzolans, which have Al and Si oxide compounds in their structures and carry little or no hydraulic characteristics. In this study, mechanical and physical characteristics of geopolymer mortars manufactured with ground granulated blast furnace slag (GGBFS) and activated with sodium silicate (water glass) were determined and also their SEM-EDS analyses were performed. As a result of the study, it was determined that geopolymers prepared with GGBFS can also be used in the areas where blast furnace slag cement would be used.

Influence of the Air-Entraining Agent in the Concrete Coating on the Reinforcement Corrosion Process in Case of Simultaneous Action of Chlorides and Frost

Abstract The paper presents the test results to evaluate the effect of air-entraining agent addition on the intensity of reinforcement corrosion in concrete with blast-furnace slag cement in the case of simultaneous action of chloride corrosion and frost. Two groups of reinforced concrete specimens were prepared for the study. The first group of specimens included air-entraining agent addition and the other group was prepared without air-entraining agent. The blast-furnace slag cement (CEM III/A) was used for the specimens. Two parallel reinforcing rods were placed in each specimen. The specimens were subjected to 120 cycles of freezing and thawing in 3% NaCl solution to induce corrosion on the reinforcement. To determine the occurrence of the reinforcement corrosion and estimate the corrosion activity the non-destructive electrochemical galvanostatic pulse method was used. On each specimen the corrosion current density of the reinforcement was measured as well as the reinforcement stationary potential and the concrete coating resistivity, i.e. values indicating the ongoing reinforcement corrosion. Measurements were made on all specimens in two steps: before freezing and thawing cycles in 3% NaCl solution and after the cycles. The analysis of the obtained results allowed to determine differences in corrosion processes intensity on the reinforced bars in the concrete specimens depending on whether or not the air-entraining agent was added. Based on the analysis it was found that in the case of simultaneous action of chloride corrosion and frost it is advisable to use both blast-furnace slag cement and air-entraining agent. The use of only blast-furnace slag cement (although it is a chloride resistant cement), without the addition of air-entraining agent is insufficient.

Influence of Silicone Oil on Durability of Portland Blast Furnace Slag Cement Mortar

Influence of Silicone Oil on Durability of Portland Blast Furnace Slag Cement Mortar

Assessing the corrosion performance for concrete mixtures made of blended cements

Although it has been used worldwide for decades, manufacturing of Blast Furnace Slag Cement (CEM III/A) has boomed since it was specified in the Egyptian Cement Standard ESS 4756 on 2006. However, corrosion protection efficiency of the Egyptian (CEM III/A) cement has rarely investigated. Therefore, in this research work corrosion performance was investigated for different concrete mixtures made of Egyptian manufactured (CEM III/A 42.5N), (CEM III/A 42.5N) partially replaced with fly ash and Ordinary Portland cement (CEM I). A total of 432 reinforced concrete (i.e. lollipop) specimens were exposed to impressed current accelerated corrosion technique. In addition to the cement types, the corrosion influence of the concrete mixture water/binder (w/b) ratio and cement content were assessed as well as the impact of reinforcement cover and exposure duration on reinforced concrete specimen’s corrosion performance. The corrosion protection was assessed by the corrosion current and it was quantified by measuring the rebar diameter loss. The chloride ion penetrability, water permeability and measured corrosion current were significantly reduced by replacing (CEM I) with either (CEM III/A) or (CEM III/A + FA) cements specially for large reinforced concrete cover having optimum cement content and minimum w/b ratio with suitable workability.