Moisés Frías

Spanish National Research Council | CSIC · Eduardo Torroja Institute for Construction Science (IETcc)

Biomass ash is currently attracting the attention of science and industry as an inexhaustible eco-friendly alternative to pozzolans traditionally used in commercial cement manufacture (fly ash, silica fume, natural/calcined pozzolan). This paper explores a new line of research into Marabou weed ash (MA), an alternative to better-known conventional...

The present work investigates the impact of particle size reduction of traditional ceramic materials as partial substitutes for Portland cement in mortars. Ceramic brick, ceramic tile, and stoneware were selected, with three particle sizes (D50 of 1, 5, and 15 μm) achieved through grinding operations adapted to each material grindability. The react...

This paper presents the characterization of a binary mixture of construction and demolition waste (CDW) and bamboo leaf ash (BLAsh) calcined at 600 °C (novel mixture) and the study of its pozzolanic behavior. Different dosages in a pozzolan/Ca(OH)2 system were employed. The aim is the valorization of fine-fraction CDW that achieves a more reactive...

This paper explores the potential of three industrial alkaline waste materials- concrete construction and demolition waste (CDW-C), white ladle furnace slag (LFS) and biomass ash (BA) –for use as secondary raw materials in the manufacture of future eco-cements with a reduced carbon footprint. Circularity is one of the key strategies behind the circ...

This research aims to analyze the effect of functionalized nanosilica (NSF) with different levels of amine groups in the formation of hydration products. Four cement pastes were investigated, one reference with Portland cement and three replacing 1% of Portland cement by nanosilica (NS), NSF with a low content of amine groups, and NSF with a high c...

Cement is a construction material widely used to improve the socio-economic development of a society. However, for its production path, it needs significant amounts of raw materials (limestone, clay, bauxite, etc.), which is currently outside the Environmental Policies. For this reason, any alternative to manufacture sustainable eco-cement based on...

The constant environmental and social pressure on the search for alternative and clean technologies has strongly influenced the construction industry, which is considered as one of the main contributors to global warming due to the emission of carbon dioxide (CO 2). The objective of this study was to evaluate the effect of partial replacement of ce...

Construction and demolition waste (CDW) currently constitutes a waste stream with growing potential use as a secondary raw material in the manufacture of eco-cements that offer smaller carbon footprints and less clinker content than conventional cements. This study analyzes the physical and mechanical properties of two different cement types, ordin...

This study reports on the microstructure of Portland cement pastes with nanosilica (NS) and amino-functionalized nanosilica (NSF). For this, NSF dispersion was prepared in a two-phase reaction system, consisting of an aqueous dispersion with dichloromethane, using 3-aminopropyltriethoxysilane (APTES):NS molar ratio 1:28.62. Cement pastes were analy...

Supplementary cementitious materials (SCMs) are commonly used in the manufacture of commercial cements with lower clinker content and carbon footprints, enabling environmental and performance improvements. The present article evaluated a ternary cement combining 23% calcined clay (CC) and 2% nanosilica (NS) to replace 25% of the Ordinary Portland C...

The serious technical and environmental problems associated with the management of construction and demolition wastes (CDW) have led to a worldwide growing interest in the recycling of that waste stream as secondary raw material for sustainable building applications. This research work investigates the physical and mechanical behaviour of mortars m...

The study described sought further understanding of the synergies in a mix of CDW pozzolans, containing (calcareous and siliceous) concrete and glass waste, used to prepare ternary eco-cement paste bearing 7% of the binary blend at concrete/glass ratios of 2:1 and 1:2. The mineralogical phases in the 2-day, 28-day, and 90-day cement matrices were i...

Las plantas invasoras proceden de ámbitos diferentes en los que se manifiestan de manera prolífica, crean comunidades resistentes que tapizan los suelos de manera indiscriminada y caótica. El marabú (Dichrostachys cinerea) es una de estas especies que, procedente de Europa, se ha instalado de una manera incontrolada en Cuba. La abundancia de esta p...

This research work focuses on the performance of mortars containing ichu ash as a potential environmentally-sound alternative to traditional pozzolans (at 6% and 10% replacement levels) under CO2 and chloride ion rich environments, in order to evaluate the capacity of this material to produce more sustainable and durable blended cements. The result...

In recent years, the development of ternary cements has become a priority research line for obtaining cements with a lower carbon footprint, with the goal to contribute to achieve climate neutrality by 2050. This study compared ordinary Portland cement (OPC) durability to the performance of ternary cements bearing OPC plus 7% of a 2:1 binary blend...

This article reports new scientific evidence on the hydrated phases present in blended cement pastes formulated with 10%, 20% or 25% metakaolin (MK) and stored at 60 °C for 15 years. XRD-Rietveld, SEM/EDX, NMR, FT-IR and TG/DTG findings attested to substantial difference in the mineralogy and morphology of the phases present (C2ASH8, C4AH13 and hyd...

Construction contributes substantially to climate change, given its intense use of natural resources, high energy demand, and raw material transport-/end product manufacture-related greenhouse gas emissions, which account for 33%–38% of the worldwide total. Against that backdrop, the sector has a vested interest in implementing strategies that atte...

Calcareous and siliceous CDW wastes from concrete and glass wastes when mixed in binary mixtures has been analyzed in this study. Fine CDW fractions (<5 mm) of different sorts are selected: siliceous waste (HsT), calcareous waste (HcG) and laminated glass waste. The binary mixtures HsT/glass and HcG/glass at mix-proportions of 1:1, 2:1 and 1:2, res...

Converting construction and demolition waste (CDW) into secondary raw materials is one of the priorities of environmental policy and circular economy strategy. This study analysed the variation in eco-efficient paste reactivity with OPC replacement ratio (5% to 10%) and hydration time (2 d, 28 d and 90 d). Three types of CDW were explored: two (cal...

It is well known that the most important issue of cement-based composites is the durability of the natural fibers. The present study evaluates the effect of activated coal mining residues on the physical-mechanical properties of fiber cement composites reinforced by thermally treated eucalyptus pulp, before and after accelerated aging. The results...

In this research work, the quantitative characterization of a binary blend comprised of two pozzolans (sugar cane straw (SCSA)–sugar cane bagasse ashes (SCBA), bamboo leaf ash (BLAsh)–SCBA and paper sludge (PS)–fly ash (FA)) taking into account the calculated values of the kinetic parameters of the reaction in the pozzolan/calcium hydroxide system...

This study analysed the effect of simultaneously replacing 0% to 100% natural with recycled concrete coarse aggregate and natural fines with 50% recycled concrete or mixed CDW fines. Characterisation of these new secondary raw materials is followed by an analysis of the effect of their use on the fresh and hardened state properties of the resulting...

This study evaluates the sulphate resistance of blended cement derived from the addition of thermally activated coal waste as pozzolan, at replacement levels of 0%, 20% (CMW20) and 50% (CMW50) with a multi-method approach. The pastes were prepared at a w/b ratio of 0.5, using a water-reducing admixture in the blended pastes to compensate for their...

This work analyses the influence of fine concrete fractions (<5 mm) of different natures —calcareous (HcG) and siliceous (HsT)—obtained from construction and demolition waste (C&DW) on the behaviour of blended cement pastes with partial replacements between 5 and 10%. The two C&DW fractions were characterised by different instrumental techniques. S...

Coal washing waste was studied as supplementary cementitious material to evaluate it as new raw materials for ecocements. The influence of temperature (room temperature, 450, 650, and 800 °C) and residence time in the muffle furnace (1, 2, and 3 h) on the mineralogy and pozzolanic properties of coal washing waste was analyzed. Different characteriz...

The construction industry and more particularly cement manufacture industry are European Green Deal strategic priorities for the circularity of Europe’s construction and demolition waste (CDW) stream with a view to reducing CO2 emissions. The industry is engaged in a number of strategies to that end, one of which is to manufacture new low-carbon, l...

The use of renewable energies and, more specifically, the existence of biomass-fired heat and power plants are being driven by European sustainability policies promoting nonfossil fuel-based power generation. The drawback is the generation of vast volumes of biomass ash (BA), both in the form of biomass bottom ash (BBA) and biomass fly ash (BFA). B...

The recent and growing trend to manufacture concrete with aggregate recycled from construction and demolition waste has contributed to the implementation of circular economy principles in the construction industry. That in turn has driven interest toward developing models to simulate the behavior of recycled aggregate concrete, which is more comple...

To address some of the gaps in the present understanding of the behavior of new supplementary cementitious materials such as bottom ash (BA) from biomass-fired electric power plants in cement manufacture, this study explored the effect of this promising material on the sulfate resistance of the end product. Cement paste prepared with 10% or 20% (pr...

This study explores the effect on sulfate resistance of the use of ornamental granite industry waste as a supplementary cementitious material (at replacement ratios of 10% and 20%) in cement manufacture. The present paucity of scientific knowledge of the behaviour of these new cements when exposed to an external source of sulfates justifies the nee...

Photoluminescence Spectroscopy was used in order to further understand cement hydration within the first hours of hydration (1 until 1024 min). The results showed a formation of C-S-H initially after 1 min of hydration and a growing process up to 32 min. This growth process fluctuates in a sinusoidal trend with the crystallographic arrangement (str...

This study analysed the fine particle (<5 mm) waste generated during siliceous or calcareous (depending on the composition of the original aggregate) concrete waste crushing. In the absence of industrial applications, such waste is amassed in open-air stockpiles on construction and demolition wastes (CDW) management plant grounds. The aim pursued w...

Silica fume is the most performing siliceous product among the pozzolanic materials. This is mainly related to his high content (around of 90%) of amorphous silica. However, this residue has a high cost and the quantities available are limited. This limits its use in the modern construction industry, particularly in developing countries. For this r...

The present research study analyses, for the first time, the viability of using thermally activated ichu grass as a supplementary cementitious material for the design of future eco-cements. To this end, the ichu ash resulting from the activation was characterised and its pozzolanic activity, the evolution of its mineralogical phases during the pozz...

Industrial waste and by-products are being widely used by the cement industry to enhance process efficiency and sustainability, in keeping with EU circular economy guidelines. This study assessed the properties of newly designed cements bearing fired clay-based C&DW against European standards. The findings showed that the blended cements met all th...

Non-fossil alternative fuels from biomass (agro-industrial, forestry and fodder plants) focus on getting cleaner, cheaper and more environmentally friendly energy sources directly related to the sustainable development of future societies. The resulting ash produced from the biomass calcination is a viable alternative for use as supplementary cemen...

The identification of new supplementary cementitious materials (SCMs) for use in blended cements is an area of major interest to the scientific community. The industry is equally keen for, given the vast amounts of raw materials and emission of large volumes of greenhouse gases involved in cement manufacture, it is under pressure to reduce its envi...

This study explores the effect of replacing 10% and 20% of portland cement with BBA from three biomass-fired power plants on new design cement sorptivity, capillary absorption, electrical resistivity, drying shrinkage, expansion and heat of hydration. The findings show that although this addition induces an increase in water uptake due to its effec...

One of the problems addressed by the scientific community in connection with cement matrix hydration is the evolution of hydrated phases under certain, primarily temperature-related, curing conditions. Such conditions are of utmost importance when the cement generates metastable hydrated phases that develop into stable phases, inducing substantial...

One source of kaolinite-rich wastes is from mine tailings and the generation of enormous volumes of mine tailings waste is standard practice in this industry. These volumes of waste are, at present, dumped, provoking significant environmental impact and transforming the environment. The present investigation has the objective of expanding the knowl...

Blending supplementary cementitious materials with portland cement is one of the current strategies for producing more eco-efficient binders by lowering the energy consumption and CO2 emissions intrinsic to OPC manufacture. The effect of such additions on heat of hydration and energy performance is a subject of particular interest, for higher heat...

This study explores certain indirect, water transport-related durability indicators for mortars made with cement in which 20% or 50% of the ordinary portland cement (OPC) is replaced by thermally activated coal mining waste (ACMW). The valorisation of ACMW is triply beneficial, environmentally speaking, for it reduces waste stockpiling and its proc...

The use of biomass to produce electric power and heat will intensify in the years to come, in pursuit of sustainable growth. Stockpiling the vast amounts of fly and bottom ash generated in that process wastes resources and has an adverse impact on the environment. The viability of bottom ash as a supplementary cementitious material in new eco-effic...

A chloride-induced accelerated corrosion test was conducted on steel bars embedded in mortar specimens prepared with thermally activated coal mining waste (ACMW). ACMW was observed to prompt two opposite effects: a delay in chloride ion penetration and a reduction in the critical chloride content needed to initiate corrosion. Service life predictio...

This pioneering study reports on the investigation of C-S-H in as-produced ternary cement pastes while highly reactive supplementary cementitious materials, such as silica fume (SF) and metakaolin (MK), and colloidal nanosilica (NS) are included into the mixtures. Several techniques are used to evaluate the microstructure of the pastes containing c...

This detailed study of the effect of three mineral additions (limestone, rice husk ash and activated coal mining waste) differing in composition and properties explored the behaviour of blended cements with a 25% replacement ratio. The aim was to select the optimal addition for improving the performance of natural fibre-reinforced cements. The pozz...

The cement industry, aware of the environmental benefits of partially replacing clinker with supplementary cementitious materials (SCMs), has been including SCMs in its manufacturing process. This paper analyses the effect of one such material, granite waste, on the hydration and mechanical performance of new blended cements and discusses the resul...

The phenomena involved in portland cement hydration and interactions with nanosilica are very complex and not yet fully understood. In addition, few papers have currently proposed to investigate the microstructure and mechanical properties of ternary mixtures using portland cement, colloidal nanosilica, and highly reactive mineral additions. This a...

Con el propósito de reducir la emisión de CO2 en la producción de cemento, incrementar el aprovechamiento de residuos y generar materias primas alternativas con mayor disponibilidad y potencial de uso, se han venido estudiando nuevos materiales capaces de desarrollar propiedades cementicias, especialmente residuos industriales, que permiten disminu...

The use of industrial waste as a cement addition often changes the composition and development of the hydrated phases and with them matrix performance and durability, in particular at later ages. The effect of the presence in blended cement of 20% to 50% kaolinite based activated carbon waste (ACW) on paste hydration has been characterized by means...

The present work contains an approach to the evaluation of binary cements prepared with a 20% substitution of coal-mining waste and their behaviour under a maximum of 300 freeze/thaw cycles. Mineralogical studies are conducted, as well as tests on mass variations, compressive strength, microporosity, the dynamic modulus of elasticity, and SEM morph...

In this study, the effect of the addition of a thermally activated coal mining waste (CMW) on the chloride permeability of blended cements in amounts from 10 to 50% was assessed by salt ponding test. The parameters involved in the infiltration of chloride have been evaluated by XRD, TG and MIP techniques, as well as by electric resistivity measurem...

This study explored the interaction between rice husk ash (RHA) and fly ash (FA) as partial (0%, 15% or 30%) additions in new ternary cements designed to reduce cement industry energy consumption and greenhouse gas (GHG) emissions by lowering their clinker content. To that end, the effect of the introduction of mixed RHA and FA on the pozzolanicity...

Cements prepared to new designs in which different types of waste are used as additions must be tested for mechanical strength and durability to ensure their performance will be satisfactory throughout their service life. This study explored the effect of adding 10% or 20% granite quarry dust to cement on properties such as transport (total and cap...

Ornamental stone quarries generate huge volumes of waste. The valorisation of such waste as possible additions (supplementary cementitious materials) to cement would contribute to the implementation of circular economy criteria in the construction industry. The study reported here constitutes a first-time analysis of the pozzolanicity and morpholog...

In recent years, agro-industrial residues have focused attention in the scientific community as a new source of pozzolans. In Brazil, for example, one of the wastes generated from agro-industrial activities comes from elephant grass that is cultivated as biomass for energy cogeneration. This study evaluated the effect of hot water treatment on the...

In the context of cement industry sustainability and socio-economic development, one of the primary objectives of the circular economy is the use of industrial waste as a supplementary cementitious material in the manufacture of future eco-efficient binders. This paper reports a first-time study of the effect of large proportions of the activated c...

The decay in mortar and concrete induced by extremely aggressive agents is normally the result of the agent‐binder reaction. Cement composition and characteristics therefore determine the durability of the mortars and concretes of which they form part. The existing legislation envisages the use of different types of additions in cement, which have...

The cement industry involves high-energy consumption that generates high CO2 emissions into the atmosphere. Environmental concerns can be addressed by replacing parts of Portland cement clinkers with pozzolanic materials in mortars and concrete. Slag, fly ash and silica fume are materials considered for the planned replacement. Research studies on...

In light of the large amounts of cement used in plain concrete and given the exothermal reactions involved in its hydration, the control and assessment of heat of hydration are instrumental to prevent future shortcomings in structural durability. This article describes the design of new eco-efficient cements containing different percentages of fire...

The worldwide pursuit of new eco-efficient pozzolans is ongoing. Kaolinite-based waste is an eco-friendly source of recycled metakaolinite, a highly pozzolanic product. In this study, a blended cement paste containing 20% activated coal waste (ACW) was exposed to a 100% CO2 atmosphere at 65% RH for 7 days. The variations in its phase composition an...