scholarly journals Low-Carbon Concrete Based on Binary Biomass Ash–Silica Fume Binder to Produce Eco-Friendly Paving Blocks

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1534 ◽  
Author(s):  
André Henrique Campos Teixeira ◽  
Paulo Roberto Ribeiro Soares Junior ◽  
Thiago Henrique Silva ◽  
Richard Rodrigues Barreto ◽  
Augusto Cesar da Silva Bezerra
Keyword(s):  
Organic Matter ◽  
Portland Cement ◽  
Silica Fume ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Alkali Activation ◽  
Low Carbon ◽  
Biomass Ash ◽  
Microstructural Investigation ◽  
Alkali Activated

The civil construction industry consumes huge amounts of raw materials and energy, especially infrastructure. Thus, the use of eco-friendly materials is indispensable to promote sustainable development. In this context, the present work investigated low-carbon concrete to produce eco-friendly paving blocks. The binder was defined according to two approaches. In the first, a binary binder developed with eucalyptus biomass ash (EBA) and silica fume (SF) was used, in total replacement for Portland cement. In the second, the mixture of residues was used as a precursor in alkali-activation reactions, forming alkali-activated binder. The experimental approach was carried out using five different mixtures, obtained by varying the amount of water or sodium hydroxide solution. The characterization of this new material was carried out using compressive strength, expandability, water absorption, deep abrasion, microstructural investigation, and organic matter degradation potential. The results showed that the EBA-SF system has a performance compatible with Portland cement when used as an alternative binder, in addition to functioning as a precursor to alkali-activated concrete. The blocks produced degraded organic matter, and this degradation is more intense with the incidence of UV. In this way, the EBA-SF binder can be successfully used for the manufacture of ecological paving blocks with low carbon emissions.

scholarly journals Live-Scale Testing of Granular Materials Stabilized with Alkali-Activated Waste Glass and Carbide Lime

2021 ◽  
Vol 11 (23) ◽  
pp. 11286
Author(s):  
Marina Paula Secco ◽  
Débora Thaís Mesavilla ◽  
Márcio Felipe Floss ◽  
Nilo Cesar Consoli ◽  
Tiago Miranda ◽  
...  
Keyword(s):  
Portland Cement ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Fine Sand ◽  
Field Application ◽  
Natural Soil ◽  
In Situ Tests ◽  
Alkali Activated

The increasingly strong search for alternative materials to Portland cement has resulted in the development of alkali-activated cements (AAC) that are very effective at using industrial by-products as raw materials, which also contributes to the volume reduction in landfilled waste. Several studies targeting the development of AAC—based on wastes containing silicon and calcium—for chemical stabilization of soils have demonstrated their excellent performance in terms of durability and mechanical performance. However, most of these studies are confined to a laboratory characterization, ignoring the influence and viability of the in situ construction process and, also important, of the in situ curing conditions. The present work investigated the field application of an AAC based on carbide lime and glass wastes to stabilize fine sand acting as a superficial foundation. The assessment was supported on the unconfined compressive strength (UCS) and initial shear modulus (G0) of the developed material, and the field results were compared with those prepared in the laboratory, up to 120 days curing. In situ tests were also developed on the field layers (with diameters of 450 and 900 mm and thickness of 300 mm) after different curing times. To establish a reference, the mentioned precursors were either activated with a sodium hydroxide solution or hydrated with water (given the reactivity of the lime). The results showed that the AAC-based mixtures developed greater strength and stiffness at a faster rate than the water-based mixtures. Specimens cured under controlled laboratory conditions showed better results than the samples collected in the field. The inclusion of the stabilized layers clearly increased the load-bearing capacity of the natural soil, while the different diameters produced different failure mechanisms, similar to those found in Portland cement stabilization.

scholarly journals Research on Eco-friendly Alkali Activated Concrete Incorporating Industrial Wastes

2019 ◽  
Vol 8 (9S2) ◽  
pp. 477-482
Keyword(s):  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Industrial Wastes ◽  
Liquid Sodium ◽  
Alkali Activation ◽  
Waste Glass Powder ◽  
Fine Aggregates ◽  
Alkaline Activator ◽  
Alkali Activated Concrete ◽  
Alkali Activated

In the present scenario, the production of green and sustainable concrete has become a must to substitute the ordinary Portland cement (OPC) concrete. It is an eminent fact that the manufacture of OPC requires burning of its raw materials which lead to a huge amount of carbon dioxide liberation; thus it requires a large amount of energy dissipation. The concrete produced using alkali activation has become renowned methods to replace the conventional OPC, which gives an answer to find a way to produce environmentally friendly concrete. In the current study, the alkaline activator used to activate the binder was sodium hydroxide solution dispersed in liquid sodium silicate. The utilization of industrial dissipate materials such as GGBS, fly ash, and waste glass powder was used as the binding ingredients, and stone crusher dust was used as fine aggregates. The experimental investigation showed that a quality concrete can be easily produced using alkali activation of industrial wastes satisfying its strength requirements. The statistical models developed shown that there is a significant relationship between various cube and cylinder strengths. Thus alkali-activated concrete(AAC) can effectively reduce the environmental hazards associated with OPC concrete, which also provides an effective way of utilizing major industrial byproducts

scholarly journals Volcanic Ash as a Sustainable Binder Material: An Extensive Review

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1302
Author(s):  
Andrés Játiva ◽  
Evelyn Ruales ◽  
Miren Etxeberria
Keyword(s):  
Chemical Composition ◽  
Portland Cement ◽  
Urban Areas ◽  
Volcanic Ash ◽  
Mechanical Performance ◽  
Cement Clinker ◽  
Alkali Activation ◽  
Cement Production ◽  
Sustainable Solutions ◽  
Alkali Activated

The construction industry is affected by the constant growth in the populations of urban areas. The demand for cement production has an increasing environmental impact, and there are urgent demands for alternative sustainable solutions. Volcanic ash (VA) is an abundant low-cost material that, because of its chemical composition and amorphous atomic structure, has been considered as a suitable material to replace Portland cement clinker for use as a binder in cement production. In the last decade, there has been interest in using alkali-activated VA material as an alternative material to replace ordinary Portland cement. In this way, a valuable product may be derived from a currently under-utilized material. Additionally, alkali-activated VA-based materials may be suitable for building applications because of their good densification behaviour, mechanical properties and low porosity. This article describes the most relevant findings from researchers around the world on the role of the chemical composition and mineral contents of VA on reactivity during the alkali-activation reaction; the effect of synthesis factors, which include the concentration of the alkaline activator, the solution-to-binder ratio and the curing conditions, on the properties of alkali-activated VA-based materials; and the mechanical performance and durability properties of these materials.

scholarly journals Fayalite Slag as Binder and Aggregate in Alkali-Activated Materials—Interfacial Transition Zone Study

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 1 ◽  
Author(s):  
Adediran ◽  
Yliniemi ◽  
Illikainen
Keyword(s):  
Transition Zone ◽  
Sodium Hydroxide Solution ◽  
Coal Fly Ash ◽  
Construction Materials ◽  
Fine Powder ◽  
Silicate Solution ◽  
Interfacial Transition Zone ◽  
Alkali Activation ◽  
Fayalite Slag ◽  
Alkali Activated

Alkali-activated materials (AAMs) are an environmentally friendly option for Portland cement mortars and concretes. Many industrial residues such as blast furnace slag and coal fly ash have been extensively studied and applied as AAM precursors but much less focus has been on the use of fayalite slags. Water-cooled fayalite slag comes in granular form, which is then milled into fine powder (d50 ~10 microns) prior to its alkali activation. In addition, the un-milled granular fayalite slag can be used as an aggregate to replace sand in mortar. The alkaline solution utilized for the study was a mix of 10 M sodium hydroxide solution and commercial potassium silicate solution. A liquid to solid ratio of 0.15 was held constant for all the mixes. The particle size distributions of the binder and the aggregates were optimized, and the microstructure and chemical composition of the interfacial transition zone (ITZ) was studied using scanning electron microscope coupled with energy dispersive X-ray spectroscopy. ITZ is a region that exists between the aggregate and the binder and this can influence the mechanical and transport properties of the construction materials. The results showed that the mechanical properties of mortar having fayalite slag as aggregate and binder was significantly higher than one with standard sand as aggregate. No distinct ITZ was found in the samples with fayalite slag as aggregate. The outer rim of the fayalite slag aggregate participated in the hardening reaction and this significantly contributed to the bonding and microstructural properties of the mortar samples. In contrast, an ITZ was observed in mortar samples with standard sand aggregates, which contributed to its lower strength.

scholarly journals Mechanical Properties of Alkali Activated Material Based on Red Clay and Silica Gel Precursor

2021 ◽  
Vol 25 (1) ◽  
pp. 931-943
Author(s):  
Girts Bumanis ◽  
Danute Vaiciukyniene
Keyword(s):  
Silica Gel ◽  
Raw Materials ◽  
Raw Material ◽  
Alkali Activation ◽  
Production Plant ◽  
X Ray Diffraction ◽  
Red Clay ◽  
Significant Strength ◽  
Naoh Solution ◽  
Alkali Activated

Abstract The search for alternative alumosilicates source for production of alkali activated materials (AAM) is intensively researched. Wide spread of natural materials such as clays and waste materials are one of potential alternatives. In this research AAM was made from local waste brick made of red clay and calcined low-carbonate illite clay precursor and its properties evaluated. Waste silica gel containing amorphous silica from fertilizer production plant was proposed as additional raw material. 6 M and 7 M NaOH alkali activation solutions were used to obtain AAM. Raw materials were characterized by X-ray diffraction, laser particle size analyser, DTA/TG. Raw illite clay was calcined at a temperature of 700 to 800 °C. Waste brick was ground similar as raw clay and powder was obtained. Replacement of red clay with silica gel from 2–50 wt.% in mixture composition was evaluated. Results indicate that the most effective activator was 6 M NaOH solution and AAM with strength up to 13 MPa was obtained. Ground brick had the highest strength results and compressive strength of AAM reached 25 MPa. Silica gel in small quantities had little effect of AAM strength while significant strength reduction was observed with the increase silica gel content. The efflorescence was observed for samples with silica gel.

scholarly journals A Step by Step Methodology for Building Sustainable Cementitious Matrices

2020 ◽  
Vol 10 (8) ◽  
pp. 2955 ◽  
Author(s):  
Styliani Papatzani ◽  
Kevin Paine
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
Carbon Footprint ◽  
State Of The Art ◽  
Cost Effective ◽  
Strength Development ◽  
Low Carbon ◽  
Current State ◽  
First Time

In an effort to produce cost-effective and environmentally friendly cementitious binders. mainly ternary (Portland cement + limestone + pozzolanas) formulations have been investigated so far. Various proportions of constituents have been suggested, all, however, employing typical Portland cement (PC) substitution rates, as prescribed by the current codes. With the current paper a step by step methodology on developing low carbon footprint binary, ternary and quaternary cementitious binders is presented (PC replacement up to 57%). Best performing binary (60% PC and 40% LS (limestone)) and ternary formulations (60% PC, 20% LS, 20% FA (fly ash) or 43% PC, 20% LS 37% FA) were selected on the grounds of sustainability and strength development and were further optimized with the addition of silica fume. For the first time a protocol for successfully selecting and testing binders was discussed and the combined effect of highly pozzolanic constituents in low PC content formulations was assessed and a number of successful matrices were recommended. The present paper enriched the current state of the art in composite low carbon footprint cementitious binders and can serve as a basis for further enhancements by other researchers in the field.

scholarly journals Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

2021 ◽  
Vol 36 (2) ◽  
pp. 182-191
Author(s):  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Sabina Dolenec ◽  
Katarina Ster ◽  
Mustafa Hadzalic ◽  
...  
Keyword(s):  
Construction Industry ◽  
Natural Radioactivity ◽  
Red Mud ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Polymerization Process ◽  
Alkali Activation ◽  
Silica Alumina ◽  
Alkali Activated

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milici, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.

scholarly journals Experimental Evaluation of the Mechanical Strengths and the Thermal Conductivity of GGBFS and Silica Fume Based Alkali-Activated Concrete

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7717
Author(s):  
Eliana Parcesepe ◽  
Rosa Francesca De Masi ◽  
Carmine Lima ◽  
Gerardo Maria Mauro ◽  
Giuseppe Maddaloni ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silica Fume ◽  
Raw Materials ◽  
Carbon Dioxide Emission ◽  
Experimental Tests ◽  
Ambient Conditions ◽  
Environmental Aspect ◽  
Mechanical Strengths ◽  
Alkali Activated Concrete ◽  
Alkali Activated

Alkali-activated concrete (AAC) could be a solution to use a cement-less binder and recycled materials for producing concrete reducing the carbon dioxide emission and the demand for raw materials, respectively. In addition to the environmental aspect, AACs can achieve mechanical characteristics higher than those of ordinary Portland concrete (OPC) but also an improvement of the thermal insulation capacity. Despite the positive results available in the scientific literature, the use of AACs in construction practice is still limited mainly due to the absence of codification for the mix design and consequently of specific design rules. In this paper, AAC produced by ground-granulated blast-furnace slag (GGBFS) and silica fume is investigated for the production of structural elements and to discuss the reliability of formulations for evaluating mechanical properties, necessary for structural design. The mechanical strengths (compression strength, tensile strength, flexural strength) are evaluated by experimental tests according to different curing times (7, 14, 28, 90 days) in ambient conditions and the thermal conductivity is measured to understand the effect that the material could have on thermal losses for a sustainable building perspective. The results showed that AAC strengths depend on the curing time and the exposure conditions, and the insulation properties can be improved compared to the traditional Portland cement with the proposed composition.

Alkali Activated Binders Based on Metakaolin

2015 ◽  
Vol 1 ◽  
pp. 200
Author(s):  
Laura Sele ◽  
Diana Bajare ◽  
Girts Bumanis ◽  
Laura Dembovska
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Raw Materials ◽  
Sodium Silicate Solution ◽  
Total Porosity ◽  
Lead Silicate ◽  
Cement Production ◽  
Alkali Activated Binders ◽  
Alkali Activated

<p>According to research conducted in last 25 years, alkali activated binders have been considered as one of the most progressive alternative binders, which can effectively replace Portland cement. Production of alkali activated binders differs from the Portland cement production and is associated with lower CO2 emissions. The use of recycled industrial by-products and wastes is also possible, what corresponds to the future guidelines and principles of sustainable binder production in the world.<br />The aim of this study was to create innovative alkali activated binders by using secondary raw materials, which will be different from the ones described in the scientific literature – alkali activated binders with porous structure. Raw materials used for the binders were metakaolin containing waste, waste from aluminium scrap recycling factory and recycled lead-silicate glass; solid contents were activated with modified sodium silicate solution with an addition of sodium hydroxide.<br />The physical properties of alkali activated binders, such as density, water absorption, open and total porosity, were determined and flexural and compressive strength of hardened alkali-activated binders were tested at the age of 28 days. Durability was examined by sulphate resistance test, which was performed according to SIA 262/1, appendix D: applicability and relevance for use in practice. 40x40x160 mm prismatic specimens were used for expansion measurement and determination of compressive strength. <br />The open porosity of obtained materials was up to 45%, density from 380 to 1720 kg/m3, compressive strength up to 29,8 MPa, water absorption 6 – 114 wt.%. After analysing the results from the sulphate test it was concluded that glass additive reduced the alkali activated binder resistance to sulphate attack.</p>

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