Cement-based Products Research Articles

Mechanical properties and durability of GGBS geopolymer mortar for M sand and river sand

The increasing demand for sustainable construction materials has led to a renewed interest in geopolymer technology, which utilizes industrial by-products to create eco-friendly alternatives to traditional cement-based products. This study focuses on geopolymer mortar developed using Ground Granulated Blast Furnace Slag (GGBS), a by-product of iron production, known for its pozzolanic properties. GGBS-based geopolymer mortar not only addresses environmental concerns associated with cement production but also enhances the mechanical and durability characteristics of the final product The fly ash based geopolymer motor set slowly in an ambient temperature and needs heat curing. To overcome this limitation, GGBS powder is used as a cementious material which shows considerable gain in strength.. In this research, various formulations of GGBS-based geopolymer mortar were created by varying the ratio of GGBS to fine aggregates, the concentration of alkaline activators (such as sodium hydroxide and sodium silicate), and the curing conditions, including temperature and duration. The primary objective was to optimize these parameters to achieve superior performance characteristics in terms of compressive strength, flexural strength, and durability. The properties of geopolymeric binder prepared using the ground-grounded blast surface without using any conventional cement has been investigated. The individual properties of the GPM for 1:3 ratio, such as compressive strength, split tensile, water absorption, sportivity and acid resistivity test were determined as perrelevant Indian standards .Cubes of size (70.6X 70.6X 70.6 )mm were casted and cured in ambient condition for molarity 4M 6M and 8M with M sand. Compressive strength for 3, 7, 28 days was studied along with oven curing for 28 days. The result shows increase in strength for 8M M sand. The sorptivity test was conducted and also water absorption was studied, it shows decreased results for 8M M sand. Good and effective results were obtained for acid resistivity test and also the results obtained for porosity, sportivityand water absorption of geopolymer motor specimens also indicates the durability of geopolymer motors.

The roles of biochar as green admixture for sediment-based construction products

Routine navigational dredging generates huge quantities of marine sediment, posing significant environmental and economic burden. This research intended to explore the efficacy of wood waste biochar as a green admixture and assess the influence of different physico-chemical properties of dredged sediments on the mechanical performance of cement-based sediment products. X-ray diffraction and porosimetry analysis reflected that particle size distribution of sediments determined the pore structure formation and strength development. Thermal and calorimetry analyses showed that biochar incorporation slightly enhanced the cement hydration reaction, while its relatively large and brittle particles induced microcracks and weakened the strength of sediment products. Nevertheless, biochar addition enhanced immobilization of potentially toxic elements and organic contaminants, rendering the sediment products more environmentally acceptable. Hence, the innovative approach of this study can recycle dredged sediment and waste wood biochar to produce eco-friendly construction materials such as fill material and paving blocks.

An integrated approach using AHP and DEMATEL for evaluating climate change mitigation strategies of the Indian cement manufacturing industry

Concrete, a cement-based product is the highest manufactured and second highest consumed product after water on earth. Across the world, production of cement is the most energy and emission intensive industry hence, the cement industry is currently under pressure to reduce greenhouse gases emissions (GHGEs). However, reducing the GHGEs of the cement industry especially for developing country like India is not an easy task. Cement manufacturing industry needs to focus on significant climate change mitigation strategies to reduce the GHGEs to sustain its production. This study aims at identifying significant climate change mitigation strategies of the cement manufacturing industry in the context of India. Extant literature review and expert opinion are used to identify climate change mitigation strategies of the cement manufacturing industry. In the present study, a model projects by applying both AHP and DEMATEL techniques to assess the climate change mitigation strategies of the cement industry. The AHP technique help in establishing the priorities of climate change mitigation strategies, while the DEMATEL technique forms the causal relationships among them. Through AHP, the results of this research demonstrate that Fuel emission reduction is on top most priority while the relative importance priority of the main remaining factors is Process emission reduction - Electric energy-related emission - Emission avoidance and reduction - Management mitigation measures. The findings also indicate that the main factors, Process emission reduction, and Fuel emission reduction are categorized in cause group factors, while the remaining factors, Electric energy-related emission, Emission avoidance and reduction and Management mitigation measures are in effect group factors. Present model will help supply chain analysts to develop both short-term and long-term decisive measures for effectively managing and reducing GHGEs.

Superplasticizer-Nanosilica Compatibility: Assessment and Optimization

Nanoparticles can yield significant benefits in cement-based products but can pose problems regarding dispersion and optimal doses. This paper proposes an inexpensive methodology to compare superplasticizers in terms of their compatibility with nanosilica, providing concrete technologists with a practical tool to select the best combinations. A series of cement pastes were produced, incorporating nanosilica and two different superplasticizers at different dosages. Their fresh state performance was assessed by means of the Marsh funnel test, and their compressive strength was determined at 28 days. The compatibility between nanosilica and superplasticizers was defined and described by developing semi-empirical models. These were used to identify optimal combinations which maximize the flowability and compressive strength and minimize their variability. It was concluded that the optimization of cement pastes with nanosilica was feasible only when the superplasticizer used is highly compatible. Careful selection of the superplasticizer proved to be critical in ensuring the efficiency and cost-effectiveness of the addition of nanosilica.

Improvement of the mechanical properties of mortar and concrete using ureolytic bacteria

The construction industry uses cement, the production of which is heavy contributor to carbon dioxide (CO2) emissions and environmental damage. Any method that reduces the usage of cement could thus result in a substantial reduction of the overall carbon dioxide footprint of final cement-based products. In this study, ureolytic bacteria were used to improve the different properties of cement mortar and concrete. Properties such as compressive strength and sorptivity were studied experimentally. The experimental results showed that the compressive strength of both cement mortar and concrete increased with an increase in bacterial concentration due to microbiologically induced mineral precipitation. An optimum bacterial dosage of 107 colony-forming units (CFU)/ml was found for the maximum increase in compressive strength for both mortar and concrete. Capillary water absorption was also found to be lower for the bacterial specimens at the optimum dosage compared with that of the control specimens. Microstructural analysis, X-ray powder diffraction and field emission scanning electron microscopy confirmed the microbiologically induced mineral precipitation.

Durability and environment evaluation of an eco-friendly cement-based material incorporating recycled chromium containing slag

Abstract This study investigates the durability of cement-based materials incorporating recycled chromium containing slag (CCS), including chloride permeability, carbonation resistance, freeze-thaw cycle and microstructure development. Additionally, the environmental impacts on the cement-based material with the addition of CCS are evaluated by toxicity characteristic leaching procedure (TCLP), carbon dioxide (CO2) emission and energy consumption. The obtained results show that the durability properties of chromium containing slag concrete (CCSC) are improved based on the addition of 20–25 wt% CCS and 5–10 wt% silica fume (SF), and the hexavalent chromium (Cr(VI)) can be well immobilized in the cement-based product. Furthermore, the incorporation of recycled CCS can significantly reduce the energy consumption and CO2 emission of cement-based materials. Based on this study, it is possible to utilize the recycled CCS to produce a clean and durable eco-friendly construction product.

ASSESSMENT OF A NEW PORTLAND CEMENT COMPONENT: GROUND COAL BOTTOM ASH

Coal bottom ash is produced in electrical power stations as result of the coal combustion. Because coal fly ash and coal bottom ash are formed together in the same boiler, similar chemical and mineralogical composition is expected. The size and shape of these ashes is very different, and then, its effect on the performance must be studied. In order to get a similar grain size to that of the coal fly ash, the coal bottom ash was ground. Cement-based products are the main construction materials which manufacture requires the use of significant natural raw materials and energy. These manufacturing processes result in several types of emissions. In particular, the cement industry is under pressure to reduce CO2 emissions and some studies have shown different measures to reach CO2 reduction. For instance, reducing the clinker/cement factor will lead to a clear CO2 emission reduction. In this work, ground coal bottom ash is investigated to know its viability of being used as a new Portland cement constituent. Then, it is studied from a mechanical and durability point of view to evaluate the potential use of the coal bottom ash as an innovative binder. Ground coal bottom ash and fly ash mortars were more carbonated and exhibited a lower compressive strength than the reference mortars, but similar to each other. Keywords: coal bottom ash, Portland cement, Compressive strength, Durability

Microstructural characterization of catalysis product of nanocement based materials: A review

Cement as an essential element for cement-based products contributed to negative environmental issues due to its high energy consumption and carbon dioxide emission during its production. These issues create the need to find alternative materials as partial cement replacement where studies on the potential of utilizing silica based materials as partial cement replacement come into picture. This review highlights the effectiveness of microstructural characterization techniques that have been used in the studies that focus on characterization of calcium hydroxide (CH) and calcium silicate hydrate (C-S-H) formation during hydration process of cement-based product incorporating nano reactive silica based materials as partial cement replacement. Understanding the effect of these materials as cement replacement in cement based product focusing on the microstructural development will lead to a higher confidence in the use of industrial waste as a new non-conventional material in construction industry that can catalyse rapid and innovative advances in green technology.

Silica–Calcareous Non Fired Bricks Made of Biomass Ash and Dust Filter from Gases Purification

From the point of view of saving and conservation of natural resources, the use of alternative components in construction materials is now an international concern. In this work, the valorization of two industrial wastes with no value in the market, biomass ash and exhaust dust filter from gases purification raw materials for the production of sustainable silica–calcareous units by the method of cementation was studied. After characterization of the raw materials, bricks were manufactured by mixing different ratios of residues, biomass ash (100−50 wt%) and dust filter (0–50 wt%) formed by pressure at 10 MPa and cured in water at room temperature for 28 days. The results indicate that as the dust filter content increases, the bulk density and mechanical strength of the silica–calcareous units decrease due to the lower density and high carbonation of the filter dust residue and the higher proportion of cement-based products formed in the pozzolanic reaction. Bricks containing 90 wt% of biomass ash-10 wt% of dust filter meet the criteria established by the regulations with an apparent density of 1471 kg/m3, water absorption of 24.2%, a compressive strength of 18.2 MPa and a thermal conductivity of 0.48 W/mK. In addition, the concentration of heavy metals obtained by leaching of the silica–calcareous ecobricks did not exceed the limits established by EPA 658/2009.

Potential of the hornification treatment on eucalyptus and pine fibers for fiber-cement applications

In the industry of cement-based products, various lignocellulosic materials are used as reinforcing elements. These cellulosic materials are presented as potential alternatives because of their sustainability, low cost and technical features. However, plant fibers, in spite of good mechanical performance as reinforcement materials, exhibit a number of shortcomings in relation to durability in the alkaline environment of cementitious materials as well as dimensional variation due to their characteristic hygroscopic behavior. Thus, hornification emerges as an alternative, economic and simple pretreatment that is expected to minimize these problems. This study evaluated the physical, chemical and morphological effects of four hornification cycles on pine pulp and innovative eucalyptus pulps, both bleached and unbleached, proving that the treatment does not deteriorate the characteristics of interest of the fibers. Hornification modifies fiber surfaces and reduces their water absorption capacity, turning the pulps into more suitable materials and giving them the technical capability to reinforce brittle inorganic matrices.

Nano-Inclusions Applied in Cement-Matrix Composites: A Review.

Research on cement-based materials is trying to exploit the synergies that nanomaterials can provide. This paper describes the findings reported in the last decade on the improvement of these materials regarding, on the one hand, their mechanical performance and, on the other hand, the new properties they provide. These features are mainly based on the electrical and chemical characteristics of nanomaterials, thus allowing cement-based elements to acquire “smart” functions. In this paper, we provide a quantitative approach to the reinforcements achieved to date. The fundamental concepts of nanoscience are introduced and the need of both sophisticated devices to identify nanostructures and techniques to disperse nanomaterials in the cement paste are also highlighted. Promising results have been obtained, but, in order to turn these advances into commercial products, technical, social and standardisation barriers should be overcome. From the results collected, it can be deduced that nanomaterials are able to reduce the consumption of cement because of their reinforcing effect, as well as to convert cement-based products into electric/thermal sensors or crack repairing materials. The main obstacle to foster the implementation of such applications worldwide is the high cost of their synthesis and dispersion techniques, especially for carbon nanotubes and graphene oxide.

Utilization of Kelut’s Volcanic Ash as the Aggregate Mixture of Concrete Brick

Kelut volcano had erupted in February 2014. The eruption has produced various materials i.e. ash, sands, etc. Volcanic ash contains various elements such as Si, Al, Ca, Fe, Na and P. It is potential to be used as raw material for cement-based products. This study investigates the utilization of Kelut’s volcanic ash as the raw material of cement-brick. The Kelut’s volcanic ash was analyzed to determine the contents of iron (Fe), aluminum (Al), and silica (Si). The volcanic ash was screened to obtain 100 mesh size of ash. The volcanic ash of 100 mesh size was mixed with cement, sand, and water with ratio of 1 kg cement, 2 kg volcanic ash, and 15 kg sand (1 :2 :15). The mixture of volcanic ash, sand and cement was poured and pressed in the concrete brick mold. The concrete brick was then aerated in a room for hardening process. The experiment was repeated for another ratio of raw material (cement: volcanic ash: sand = 2:1:15) and the age of the concrete brick (46, 61, 75 and 89 days). Concrete bricks were analyzed to determine the quality and the mechanical characteristics. The results has shown that Kelut’s volcanic ash has a composition of aluminum (Al) 4.707%, silica (SiO2) 23.4%, and iron (Fe) 3.85%, that is like the composition of the cement materials. The concrete bricks which are made of cement, Kelut’s volcanic ash, and sand with the ratio of 2:1:15 has a maximum compression strength of 18.85 MPa at the age of 89 days. The addition of Kelut’s volcanic ash has improved the strength of concrete brick. However, too much volcanic ash will lead to increasing compression strength.

Impedance-Based Characterization of Functional Carbon Nano-Tube/Cement Composites

Carbon-based materials allows for their derivatives such as fullerenes, carbon nano-tubes (CNTs), and graphenes in addition to the conventional bulk carbon materials. The high conductive feature of carbon-based derivatives can be exploited as the conduction path of the carbon/inorganic mixture. In this work, carbon-based materials are combined with cement-based materials in order to being fabricated as the pressure-sensors under the high-impact condition. In particular, the CNTs are combined with cement-based materials. The corresponding hydration is monitored as a function of time using impedance spectroscopy. The addition of CNTs into the cement matrix system modifies the conventional conduction path, forming a conductive one, leading to the significant change in impedance spectra. The frequency-dependent impedance information allows for an equivalent circuit model which reflects the microstructure composed of CNTs and cement-based products. Based on the microstructural/electrical understanding, a possibility of being a piezoresistive sensor is discussed as a novel application involving the peculiar features of 1-dimensional CNT materials.

Waste-glass fume synthesized using plasma spheroidization technology: Reactivity in cement pastes and mortars

Using silica-based nanoparticles is one way to stimulate the hydration reactivity and improve the rheological properties of concrete, given their fineness and spherical shape. Based on its high content in amorphous silica ((SiO2>70wt.%), waste glass is an excellent material for valorization into pozzolanic nanoparticles or the so-called “glass fume” (GF). GF, produced using the radiofrequency induction-coupled-plasma (RF ICP) spheroidization technology, mainly consists of spherical and amorphous nanoparticles (dia. of 30–200nm). Given the scarcity and high cost silica fume (SF), its use in producing high-strength concrete is now limited. GF produced using the scalable plasma spheroidization process is currently being tested in cement-based products as an alternative for SF.The GF was characterized with field-emission-gun scanning electron microscopy (FEGSEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) specific surface, acoustic particle sizer (APS), X-ray fluorescence (XRF) and thermogravimetry coupled to mass spectrometry (TGA-MS). The hydration of GF in cement pastes and mortars was monitored in this study. The cement pastes were characterized at early age with isothermal calorimetry and as a function of curing time with X-ray diffraction (XRD) as well as with thermogravimetric analysis (TGA) and variable pressure scanning electron microscopy (VPSEM). Mortars were tested for compressive strength and their microstructure was observed with VPSEM. Also, their hydration was monitored with the electrical conductivity. The results indicate that GF offers nucleation sites for portlandite, alkalis for the activation of the cement hydration at early age, and a pozzolanic behavior for the long-term evolution of mortar properties. In mortars, the GF yielded compressive strengths equivalent to those obtained with SF used as a comparison. The GF mortars required a lower superplasticizer (SP) dosage than the SF mortar because of the ball-bearing effect induced by GF’s complete spherical morphology. In addition to spherical nanoparticles, SF contains silica-based nanofilaments, which affect the rheology of fresh cement-based materials.

Effect of cement-based solid product on the impact-echo responses of concrete cask storage for low-level radioactive wastes

Effect of cement-based solid product on the impact-echo responses of concrete cask storage for low-level radioactive wastes

Manufacturing cement-based materials and building products via extrusion: from laboratory to factory

Manufacturing is critical to the economies of the UK and many other countries in the rest of the world. However, manufacturing of cement-based materials and building products predominantly remains based on old batch-processing techniques such as casting and pressing, and this may limit the applications and performance of the materials and products formed. This paper reports on research into transforming the manufacturing of precast cement-based materials and building products from in batches to continuous processes by way of extrusion. Techniques used for producing plastic products are transferred into manufacturing cement-based building products, such as flat and corrugated sheet tiles, downpipes, door and window frames, door panels, solid wall and facade panels, and honeycomb wall and facade panels, both at laboratory and factory scales. In combination with sustainable cementitious materials with low carbon dioxide emissions and low energy consumption as the matrix, this enables sustainable building products to be manufactured by way of extrusion.

Concrete properties containing fine aggregate marble powder

The rapid growth of the marble industry introduces concerns regarding the negative impact of marble quarrying on the environment, because the cutting of marble creates sludge. The incorporation of marble sludge (powder) into concrete and cement-based products would make significant environmental and economic contributions. This study aims to develop a concrete mixture with maximum marble content that has strength properties comparable to that of the non-marble reference concrete (without marble powder), as opposed to developing a marble powder concrete with maximum compressive strength. The main purpose is to replace sand with marble powder in concrete because such a mixture will be environmentally friendly and economically feasible. The concrete samples are produced by replacing sand with marble powder at 10%, 20%, 30%, 40%, 50% and 90% by volume. The compressive strength values are determined after 7, 28 and 90 days with splitting tensile strength values at 28-th day including water absorption and abrasion resistance values. A feasibility evaluation is performed using parameters such as fresh concrete, compressive strength, sorptivity, abrasion resistance, and estimated cost. Based on the feasibility evaluation it is shown that using up to 40% marble powder in concrete is suitable in accordance with the requirements.

Making sense of opportunities in building material production

Purpose – Breakthrough improvement requires management decisions, which indicates that making sense of existing opportunities is important. This is a particular challenge when the improvement is a possibility and not a problem. The purpose of this paper is to propose the practice of doing an Opportunity Study as the way to create a sense of management urgency for realising dormant possibilities. Design/methodology/approach – A process-based Opportunity Study is presented consisting of a Diagnosing-Analysing-Solving (DAS) approach. Benchmarks are defined and compared with the actual performance resulting in a quantifiable improvement potential (D). Main causes are analysed (A), which leads to proposed solutions (S). The Opportunity Study practice is applied to a cement milling process, a cement plant and a supply network for cement-based building products. Findings – Results indicate that applying DAS methodology highlights realisable opportunities in all of the studied cases. This seems to be a necessary, but not sufficient criterion to create a sense of urgency for facts based change. Research limitations/implications – The results indicate that there is need for further research for looking at the process of sense making and to what extent facts alone can drive change initiatives. Practical implications – Results indicate that by a simple review, focusing on what a system can do instead of which the problems are, valuable opportunities for improvement could be detected. Originality/value – The paper highlights the value of focusing on opportunities.

Microstructural study on the effectiveness of commercial polymer emulsion as cement additives to mitigate efflorescence

The occurrence of calcium carbonate (CaCO 3 ) effl orescence phenomenon is not new and is generally found in the form of unsightly white deposits on the surface of cement products. It appears just after completion of building construction and causes aesthetically unpleasant sight. This paper presents and discusses the results of microstructural study on the effectiveness of commercial polymer emulsion as cement additives to mitigate effl orescence on cement-based products that are dry-cured in the concrete laboratory at daily room temperature (T) and relative humidity in the range of 18°C‐28°C and 65%‐90%, respectively. Polymers used as cement additives were styrene acrylic ester (SAE) and styrene butadiene rubber (SBR) emulsion. Due to their pore-blocking characteristics and interaction with cement to improve mortar quality, they are added into cement to form mortar used for repair purposes. In order to investigate on how they can microstructurally infl uence effl orescence formation, effl orescence intensities (EI) in terms of percentages of CaCO 3 resulting from the combination of puddle test and standard chemical method were compared systematically between all samples on 28, 60 and 90 days and the fi ndings were discussed and corroborated physicochemically using initial surface absorption test, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and morphology using scanning electron microscopy (SEM). Results indicated that 10% and 5% SAE addition signifi cantly reduced primary effl orescence and secondary effl orescence, respectively, in comparison to SBR and Control. The infl uence were on chemical reactivity, interaction between polymer and cement and on the movement of the polymer particles within the hydrating mortar as hydration progressed to form pore-blocking effects in the microstructures of cement-based materials and were refl ected in the XRD patterns, TGA/DTG analysis, SEM images and the decreased initial surface water absorption.

Recent Photocatalytic Applications for Air Purification in Belgium

Photocatalytic concrete constitutes a promising technique to reduce a number of air contaminants such as NOx and VOC’s, especially at sites with a high level of pollution: highly trafficked canyon streets, road tunnels, the urban environment, etc. Ideally, the photocatalyst, titanium dioxide, is introduced in the top layer of the concrete pavement for best results. In addition, the combination of TiO2 with cement-based products offers some synergistic advantages, as the reaction products can be adsorbed at the surface and subsequently be washed away by rain. A first application has been studied by the Belgian Road Research Center (BRRC) on the side roads of a main entrance axis in Antwerp with the installation of 10.000 m² of photocatalytic concrete paving blocks. For now however, the translation of laboratory testing towards results in situ remains critical of demonstrating the effectiveness in large scale applications. Moreover, the durability of the air cleaning characteristic with time remains challenging for application in concrete roads. From this perspective, several new trial applications have been initiated in Belgium in recent years to assess the “real life” behavior, including a field site set up in the Leopold II tunnel of Brussels and the construction of new photocatalytic pavements on industrial zones in the cities of Wijnegem and Lier (province of Antwerp). This paper first gives a short overview of the photocatalytic principle applied in concrete, to continue with some main results of the laboratory research recognizing the important parameters that come into play. In addition, some of the methods and results, obtained for the existing application in Antwerp (2005) and during the implementation of the new realizations in Wijnegem and Lier (2010–2012) and in Brussels (2011–2013), will be presented.