Service life and life cycle assessment of reinforced concrete systems with limestone calcined clay cement (LC3)
TL;DR: In this article, the authors presented data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC+PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3).
Abstract: This paper presents data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC + PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3). Using these, the service lives of a typical bridge pier and girder with the PFA and LC3 concrete were found to be much higher than those with OPC concrete of similar strength. From life-cycle assessment, the CO2 footprint of PFA and LC3 concrete were found to be significantly lower than those of OPC concrete of similar strength. Further, the CO2 emissions per unit of concrete per year of estimated service life, as a combined indicator of service life and carbon footprint, are similar for concrete with PFA and LC3, which are much lower than that with OPC.
Citations
More filters
TL;DR: A review of the literature available on the subject of the recently developed limestone calcined clay cement (LC3) can be found in this article, where an introduction to the background leading to the development of LC3 is discussed.
Abstract: This article reviews the rapidly developing state-of-the-art literature available on the subject of the recently developed limestone calcined clay cement (LC3). An introduction to the background leading to the development of LC3 is first discussed. The chemistry of LC3 hydration and its production are detailed. The influence of the properties of the raw materials and production conditions are discussed. The mixture design of concrete using LC3 and the mechanical and durability properties of LC3 cement and concrete are then compared with other cements. At the end the economic and environmental aspects of the production and use of LC3 are discussed. The paper ends with suggestions on subjects on which further research is required.
114 citations
TL;DR: In this article, a review summarises literature to examine the transition from portland limestone cement system to composite ternary binder systems involving limestone and the interaction of fine limestone is classified and elaborated under two broad umbrellas: physical and chemical interactions.
Abstract: The review summarises literature to examine the transition from portland limestone cement system to composite ternary binder systems involving limestone. Interest in limestone addition as an ideal component in multicomponent binder systems has surged as evident from the large volume of literature published in the recent past. A ternary blended system, with co-substitution of limestone, has the potential to complement the reaction of the supplementary cementitious materials (SCMs). The direct addition of limestone powder helps to attain higher substitution levels of portland cement clinker, improve early age properties, and supplement SCM's reactivity. However, the dilution of hydrates could hamper the long-term benefits. In this review, the interaction of fine limestone is classified and elaborated under two broad umbrellas: physical and chemical interactions. The physical interactions can manifest in three ways, namely, filler action, shearing action and improved packing, which alters reaction rate and extent at early ages. The chemical interactions also modify the reaction kinetics and phase assemblage due to nucleation of C-S-H on calcite surfaces, preservation of the ettringite phase and formation of carboaluminates. Two different forms of carboaluminate hydrates — hemicarboaluminate and mono-carboaluminate can be present in the hydrate matrix depending on the balance between carbonate ions and aluminates in the pore solution. Several factors such as replacement level, particle size, choice of SCM, its reactivity and reactive aluminates content, sulphate levels, curing temperature, and duration of curing can control the carboaluminate formation, reaction degree of SCMs and chemical interaction from limestone additions. A combination of physical and chemical effects makes fine limestone a potential material for co-substitution with aluminosilicate based SCMs, mainly fly ash, slag, and calcined clay. In this review, the factors affecting limestone-SCM composites are summarised based on a detailed literature survey. The effects of SCM-limestone cement composites on hydration kinetics, reaction chemistry, the reactivity of SCMs, the stability of hydrated phases, and contribution to the physical structure development and macroscopic properties by evaluating hydration and mechanical properties are discussed. The importance of AFm (Al2O3–Fe2O3-mono) phases in various deterioration mechanisms in concrete and their influence on performance characteristics in different exposure environment is critically appraised.
95 citations
ETH Zurich1, Norwegian University of Science and Technology2, Spanish National Research Council3, Delft University of Technology4, Oregon State University5, Imperial College London6, Technical University of Denmark7, Norwegian Public Roads Administration8, Technische Universität München9, University of Toulouse10, University of Córdoba (Spain)11, University of Sheffield12, University of Waterloo13, Indian Institute of Technology Madras14, Bundesanstalt für Materialforschung und -prüfung15, Rijkswaterstaat16, RWTH Aachen University17, CTLGroup18, University of South Florida19
TL;DR: In this paper, the effect of various steel-concrete interface (SCI) characteristics on the susceptibility of reinforced concrete to corrosion was investigated and the authors found that the different SCI characteristics have received highly unbalanced research attention.
Abstract: The steel–concrete interface (SCI) is known to influence corrosion of steel in concrete. However, due to the numerous factors affecting the SCI—including steel properties, concrete properties, execution, and exposure conditions—it remains unclear which factors have the most dominant impact on the susceptibility of reinforced concrete to corrosion. In this literature review, prepared by members of RILEM technical committee 262-SCI, an attempt is made to elucidate the effect of numerous SCI characteristics on chloride-induced corrosion initiation of steel in concrete. We use a method to quantify and normalize the effect of individual SCI characteristics based on different literature results, which allows comparing them in a comprehensive context. It is found that the different SCI characteristics have received highly unbalanced research attention. Parameters such as w/b ratio and cement type have been studied most extensively. Interestingly, however, literature consistently indicates that those parameters have merely a moderate effect on the corrosion susceptibility of steel in concrete. Considerably more pronounced effects were identified for (1) steel properties, including metallurgy, presence of mill scale or rust layers, and surface roughness, and (2) the moisture state. Unfortunately, however, these aspects have received comparatively little research attention. Due to their apparently strong influence, future corrosion studies as well as developments towards predicting corrosion initiation in concrete would benefit from considering those aspects. Particularly the working mechanisms related to the moisture conditions in microscopic and macroscopic voids at the SCI is complex and presents major opportunities for further research in corrosion of steel in concrete.
89 citations
Cites methods from "Service life and life cycle assessm..."
...Effect of cement type on corrosion initiation based on total Ccrit reported in [57, 62, 63, 66, 70-75]....
[...]
...PC blended with SCMs: A number of studies [57, 62, 63, 66, 70-74] reported Ccrit when using different SCMs as summarized in Fig....
[...]
TL;DR: In this article, the role of microstructure in terms of the chemical composition of C-A-S-H and its physical states in the different systems is identified as the critical factor governing the development of micro-structure.
Abstract: This paper discusses the role of physical structure alterations on three binder types: plain portland cement, fly ash-based binder and calcined clay-limestone binder. The kinetics of physical structure development and the relevance in transport properties were distinguished using an interlinked parameter in concrete and paste. A systematic experimental investigation was carried out on a range of critical parameters such as strength development, resistivity development, transport characteristics and the time-dependent change in transport parameter. The role of microstructure in terms of the chemical composition of C-A-S-H and its physical states in the different systems is identified as the critical factor governing the development of microstructure. Chloride resistance was assessed by chloride migration experiments for a period of 4 years. The durability behaviours of the concrete with various binder were generalised using pore network parameters such as formation factor and tortuosity. A sensitivity analysis was used to dissect the contribution of the pore solution dilution and pore connectivity to the change in the pore network parameter. Based on the rise in macroscopic physical characteristics (i.e., formation factor here), a two-fold structure development mechanism to conceptualise microstructural evolution in cement composites is presented. Initially, capillary pore space reduces to a critical size range (i.e., 10–30 nm), which is followed by the densification of the physical state of the microstructure. At the point of densification, the pores become largely disconnected which leads to a dramatic increase in the formation factor. The binding matrix in calcined clay concretes reaches the critical pore size at an early age which leads to early densification of capillary pore space region in comparison to fly ash concretes.
75 citations
TL;DR: In this article, a comprehensive review of the research progress on activated kaolinitic clay as SCM in the last decade is presented, which systematically introduces the essential properties, activation mechanism and pozzolanic reactivity assessment of calcined clay.
Abstract: The development of a green alternative that can partially or completely substitute the Ordinary Portland cement (OPC) as a practical construction material with low CO2 footprint is an important subject to researchers for decades. The use of artificial pozzolanic materials, e.g. fly ash, slag, silica fume, etc. cannot meet the huge-scale demand for cement replacement. Kaolinitic clay, with its high pozzolanic reactivity after activation and abundant resources worldwide, is regarded as a promising supplementary cementitious material (SCM) for cement. Recent studies have addressed that the utilization of calcined kaolinitic clay as SCM can effectively improve the properties of cement products. This paper presents a comprehensive review of the research progress on activated kaolinitic clay as SCM in the last decade. It systematically introduces the essential properties, activation mechanism and pozzolanic reactivity assessment of kaolinitic clay. Application of calcined clay in two different cementitious systems (calcined clay blended cement and limestone calcined clay cement) is reviewed from the aspects of workability, mechanical properties, and long-term durability properties with the mechanism discussion. Finally, the environmental and economic impacts of the application of calcined clay in different cementitious systems are discussed.
70 citations
References
More filters
Book•
01 Jan 1982TL;DR: In this article, the authors present a research work that aims at mapping out the various mechanisms which control the process of steel corrosion in concrete, and illustrate how steel corrosion is illustrated.
Abstract: The research work that is presented in this thesis aims at mapping out the various mechanisms which control the process of steel corrosion in concrete._x000D_ The process of corrosion is illustrate ...
1,321 citations
01 Mar 2002
TL;DR: In this paper, the authors presented the annual total cost of metallic corrosion in the United States and preventive strategies for optimum corrosion management, which is estimated at $276 billion per year, which was 3.1% of the 1998 U.S. gross domestic product.
Abstract: This report describes the annual total cost of metallic corrosion in the United States and preventive strategies for optimum corrosion management. In 1998, an amendment for a Cost of Corrosion study was included in the Transportation Equity Act for the 21st Century (TEA-21) and was approved by Congress. In the period from 1999 to 2001, CC Technologies conducted the research in a cooperative agreement with the Department of Transportation Federal Highway Administration (FHWA) and NACE International (The Corrosion Society). The total direct cost of corrosion is estimated at $276 billion per year, which is 3.1% of the 1998 U.S. gross domestic product (GDP). This cost was determined by analyzing 26 industrial sectors in which corrosion is known to exist and extrapolating the results for a nationwide estimate. The sectors were divided among five major categories: infrastructure, utilities, transportation, production and manufacturing, and government. The indirect cost of corrosion is conservatively estimated to be equal to the direct cost (i.e., total direct cost plus indirect cost is 6% of the GDP). Evidence of the large indirect corrosion costs is lost time, and thus lost productivity because of outages, delays, failures, and litigation. It was found that the sectors of drinking water and sewer systems ($36 billion), motor vehicles ($23.4 billion), and defense ($20 billion) have the largest direct corrosion impact. Within the total cost of corrosion, a total of $121 billion per year is spent on corrosion control methods and services. The current study showed that technological changes have provided many new ways to prevent corrosion and there has been improved use of available corrosion management techniques. However, better corrosion management can be achieved using preventive strategies in non-technical and technical areas. These preventive strategies include: (1) increase awareness of large corrosion costs and potential savings, (2) change the misconception that nothing can be done about corrosion, (3) change policies, regulations, standards, and management practices to increase corrosion cost-savings through sound corrosion management, (4) improve education and training of staff in recognition of corrosion control, (5) advance design practices for better corrosion management, (6) advance life prediction and performance assessment methods, and (7) advance corrosion technology through research, development, and implementation.
1,124 citations
TL;DR: In this paper, a review of the state-of-the-art in the area of critical chloride thresholding of reinforced concrete is presented, highlighting the strong need for a practice-related test method, and focusing especially on experimental procedures.
Abstract: Chloride induced corrosion as the major cause for degradation of reinforced concrete has been the subject of great research efforts over the last fifty years. The present literature review summarises the state of the art by presenting the concept of the critical chloride content, discussing influencing factors, and assessing available measurement techniques. A large number of published chloride threshold values together with the respective experimental details are collected. While today's experience is mostly based on Portland cement, more modern studies with non-traditional binders often reported contradictory results. The present literature evaluation highlights the strong need for a practice-related test method, and, in this regard, focuses especially on experimental procedures by discussing advantages and drawbacks of methods and setups. It clearly emerges that many of the setups used to determine critical chloride contents are not suited to give realistic results.
982 citations
TL;DR: In this paper, the coupled substitution of metakaolin and limestone in Portland cement (PC) was investigated and the mechanical properties were studied in mortars and the microstructural development in pastes by X-ray diffraction, thermogravimetry analysis, mercury intrusion porosimetry and isothermal calorimetry.
Abstract: This study investigates the coupled substitution of metakaolin and limestone in Portland cement (PC). The mechanical properties were studied in mortars and the microstructural development in pastes by X-ray diffraction, thermogravimetry analysis, mercury intrusion porosimetry and isothermal calorimetry. We show that 45% of substitution by 30% of metakaolin and 15% of limestone gives better mechanical properties at 7 and 28 days than the 100% PC reference. Our results show that calcium carbonate reacts with alumina from the metakaolin, forming supplementary AFm phases and stabilizing ettringite. Using simple mass balance calculations derived from thermogravimetry results, we also present the thermodynamic simulation for the system, which agrees fairly well with the experimental observations. It is shown that gypsum addition should be carefully balanced when using calcined clays because it considerably influences the early age strength by controlling the very rapid reaction of aluminates.
763 citations
TL;DR: A review of the current state-of-the-art and standards underpinning the production and use of OPC-based cements and concretes can be found in this paper.
Abstract: The cement industry faces a number of challenges that include depleting fossil fuel reserves, scarcity of raw materials, perpetually increasing demand for cements and concretes, growing environmental concerns linked to climate change and an ailing world economy. Every tonne of Ordinary Portland Cement (OPC) that is produced releases on average a similar amount of CO2 into the atmosphere, or in total roughly 6% of all man-made carbon emissions. Improved production methods and formulations that reduce or eliminate CO2 emissions from the cement manufacturing process are thus high on the agenda. Emission reduction is also needed to counter the impacts on product cost of new regulations, green taxes and escalating fuel prices. In this regard, locally available minerals, recycled materials and (industry, agriculture and domestic) waste may be suitable for blending with OPC as substitute, or in some cases replacement, binders. Fly ash, Blast furnace slag and silica fumes are three well known examples of cement replacement materials that are in use today that, like OPC, have been documented and validated both in laboratory tests and in practice. The first is a by-product of coal combustion, the second of iron smelting and the third of electric arc furnace production of elemental silicon or ferro silicon alloys. This paper presents a concise review of the current state-of-the-art and standards underpinning the production and use of OPC-based cements and concretes. It outlines some of the emerging green alternatives and the benefits they offer. Many of these alternatives rely on technological advances that include energy-efficient, low carbon production methods, novel cement formulations, geopolymers, carbon negative cements and novel concrete products. Finally, the economics of cement production and the trends in the UK, US and the Gulf Cooperation Council (GCC) Region are presented, to help guide and inform future developments in cement production based on maximizing the value of carbon reduction.
582 citations