characterization of the ground granulated blast furnace slag binder and copper slag aggregate

In the MIP result, the use of NaCl reduced capillary pores in the CaO-activated GGBFS when the gypsum was present at 7 days of curing. With the increase of TiO2 addition, the WI and L* value of the CaO-activated GGBFS increased consistently. At the given amount of TiO2, rutile reduced more extent of a* and b* value of the CaO-activated GGBFS samples compared to the anatase.

As the copper slag is added to the cement mortar, the flowability of the mortar is consistently increased. The linear damping coefficient of the cement mortar sample with 100 wt% copper slag added was 30 to 31% higher than that of the cement mortar sample with 100 wt% silica sand. In the high photon energy region, the mass attenuation coefficients of the cement mortar increased slightly and became almost constant as the photon energy was increased.

Except for the intermediate energy region, the mass softening coefficients of cement mortar added with 100 wt% copper slag were higher than that of cement mortar added with 100 wt% silica sand. Compressive strength of hardened paste samples: (a) group Ca-A and Ca-R with white cement and (b) group Na-A and Na-R.

INTRODUCTION

Needs for developing ecofriendly construction material

Since the production of cement requires a high-temperature sintering process (ie around 1400 ˚C) [2], the production of one ton of cement releases 0.9 tons of carbon dioxide [3, 4]. Accordingly, the global emission of carbon dioxide (CO2) resulting from the production of cement amounts to 5 to 8% of anthropogenic CO2 emissions [4, 5]. Since CO2 emission is the most important factor for accelerating global warming among other greenhouse gases (eg water vapor, methane, ozone, nitrous oxide) [8], carbon dioxide from cement production should be reduced.

Therefore, extensive efforts have been made to reduce CO2 emissions from the construction sector. Sustainable and environmentally friendly construction could be achieved by using an industrial by-product as a building material.

Figure 1.2 Global CO 2 emission in 1990-2020 [6].

Industrial by-product studied as a construction material

Fly ash
Bottom ash
Red mud
Slag

Normally, one to two tons of red mud is produced as a by-product when one to two tons of alumina is produced in Bayer's process [26]. During iron production, Fe ore, coke and limestone are used as raw materials to produce molten iron. Thus, air-cooled slag is used as aggregate for concrete, and GGBFS is used as supplementary cementitious material (SCM) for cement.

The molten iron produced from ironmaking is used as raw material to make molten steel with coke and liquids in the basic oxygen furnace. In the process of the non-ferrous slag, concentrating, roasting and smelting processes are generally involved. Among the slags, GGBFS also used as binder material for cement replacement which is not only used as SCMs, raw material for cement clinker and calcium silicate fertilizer.

Schematic flow diagrams of slag generation produced from copper, lead and zinc production slag Air-cooled Used as road base material, coarse aggregate in the construction sector and raw material for stone wool. It is used as asphalt concrete aggregate, basic material for cement clinker and is used in the production of fertilizers and soil improvement.

Figure 1.7. The schematic flow diagrams of slag generation produced from the iron and steel manufacturing [41]

Outline of the dissertation

In chapter 5, the mechanical properties, fluidity and radiation shielding ability of the cement mortar incorporated with copper slag as an aggregate for the development of environmentally friendly radiation shielding building material are investigated.

PROPERTIES OF RAW MATERIALS AND EXPERIMENTAL METHODS

Properties of raw materials

GGBFS
Copper slag

Copper slag is a kind of non-ferrous slag which is generated from the matte smelting and conversion process [50]. The copper slag produced from the furnace was usually cooled slowly at room temperature, creating the crystalline porous properties [35]. The chemical composition of copper slag consists of oxide form of iron, silicates, calcium and aluminium.

Copper slag has been studied as an alternative sand in the mortar/concrete in the several previous studies [51].

Figure 2.1 Schematic representation of Granulated blast furnace slag generation [36, 45].

Experimental methods

Particle size distribution
X-ray fluorescence (XRF)
Hydration stop methods
X-ray diffraction (XRD)
Thermogravimetric analysis (TGA)
Mercury intrusion porosimetry (MIP)
Spectrophotometer
Inductively coupled plasma-optical emission spectrometry (ICP-OES)
Experimental and theoretical gamma ray attenuation test

The laser diffraction particle size analyzer determined the particle size distribution of the raw material by detecting the intensity of the scattered light. Using it, we could provide the chemical composition of raw GGBFS, which affects the strength and color of GGBFS after solidification. Hydration arrest methods must completely remove free water in the cement sample while preventing damage to the reaction products and sample voids.

The reaction product of the sample can be damaged by the presence of organic solvents. In the hydrated cement and hardened GGBFS binders, C-S-H is an important reaction product, which is known as the origin of compressive strength [2]. TGA is used to complement the XRD results by analyzing the quantification of the crystalline phases in the cementitious binders found using XRD.

The existence of the air spaces can reduce the strength of the hardened cementitious binders. The capillary pores are the spaces between the hardened components of the cementitious binders that are not filled. Mercury intrusion porosimetry (MIP) is a useful tool for detecting the porosity, pore size distribution and pore volume of the cementitious binder.

The principle of MIP is based on the penetration of a mercury liquid into porous material under increasing pressure. The chromatic properties of the GGBFS binder are measured following ASTM E 313 and CIE L*a*b* system [86, 87]. The detailed explanations of the CIE L*a*b* values, CIE whiteness and CIE hue will be discussed in Chapter 4.

By analyzing the specific wavelength, the quantification of the specific atom in the cementitious binder can be known. Based on the chemical composition and density of the sample at given photon energies, theoretical gamma ray attenuation coefficients can be calculated. More detailed explanations of the theoretical attenuation coefficients of gamma rays will be discussed in chapter 5.2.2.

Figure 2.4. Particle size range of raw materials

STRENGTH ENHANCEMENT OF MIXING WATER WITH HIGH CHLORIDE

Introduction

Experimental program

Results and discussion

Compressive strength
ANOVA analysis
Powder X-ray Diffraction (XRD)
Thermogravimetric (TG) analysis
Mercury Intrusion Porosimetry (MIP)

Conclusions

Materials
Experimental Program

Compressive strength
XRD analysis
CIELAB coordinates, whiteness index, and tint index

Conclusions

INCORPORATION OF COPPER SLAG IN CEMENT BRICK PRODUCTION

Introduction

Experimental program

Materials
Preparation of samples and tests

Flowability and compressive strength
Gamma ray attenuation
Trial cement brick production and tests

Conclusion

Summary

The strength loss may be related to the increased porosity of the mortar by addition of bottom ash [20]. In the figure, the error bars represent the standard deviations of the tested results of the triplicate samples. The effect of the TiO2 addition on hue (T) depended on the type of TiO2in groups of Ca-A and Ca-B.

In Figure 4.7 (a), regardless of the type of activator and the type of TiO2, the L* value gradually increased with the increase of the added amount of TiO2. On the other hand, in the case of b* in Figure 4.7 (c), regardless of the type of TiO2, all b* values were positive for all samples. In the activation of CaO in Figure 4.8, WI was closely related to L* and b* regardless of the type of TiO2.

In the results, the linear attenuation coefficients of the sample with 100 wt% copper slag (CS100) were 30−31% higher than those of the samples with 100 wt% silica sand (CS0) at all gamma-ray energies, and the increase was most likely attributed to the higher specific gravity of copper slag than silica sand [166, 167]. In the results, the fluidity of the mortar increased with the increase of copper slag added in all doses of copper slag. The effects of TiO2 type and activation type on the compressive strength and surface color of GGBFS were studied.

The effective atomic number of the cement mortar using 100 wt% copper slag was also higher than that of the cement mortar using 100 wt% silica sand throughout the gamma-ray energy range. It was found that the measured heavy elements in the cement mortar using 100 wt% copper slag were much lower than the regulatory element concentrations specified in the TCLP. Morelli, Influence of the addition of grinding dust to a magnesium phosphate cement matrix, Construction and Building Materials.

Rajamane, Studies on the use of copper slag as a substitute material for river sand in civil engineering, Journal of the Institution of Engineers (India): Series A 95(3).

PROPERTIES OF RAW MATERIALS AND EXPERIMENTAL

STRENGTH ENHANCEMENT OF MIXING WATER WITH HIGH