P. J. M. Monteiro

P. J. M. Monteiro
University of California, Berkeley | UCB · Department of Civil and Environmental Engineering

PhD

About

399
Publications
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17,486
Citations

Publications

Publications (399)
Article
This research studied the hydration of C3S-C3A-calcium sulfate systems made of combinations of two C3S (pure triclinic and Al-doped monoclinic), two C3A (pure cubic C3A and Na-doped orthorhombic), and two calcium sulfates (gypsum and hemihydrate). For each system, the hydration of four different SO3 contents (0.25-2.0 wt%) was assessed by calorimet...
Article
Engineered cementitious composites (ECC) is a durable cementitious material with high tensile ductility and strain-hardening characteristics. Although considered as a cost-effective fiber for ECC, polypropylene (PP) fiber is reportedly difficult to disperse in mortar matrix due to its high aspect ratio and hydrophobicity. In this study, the matrix...
Article
Ten hybrid fiber reinforced concrete mixtures are designed to investigate the effect of three different steel fibers and their combination on the Mode I fracture of concrete. The fracture process and damage characteristics are studied by measuring the full-field displacement and strain on the surface of the specimen by the digital image correlation...
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In an urban built city environment, the performance of electromagnetic (EM) wave propagation through building materials poses a new set of challenges to radio frequency engineers in the prediction of the 5G‐network coverage planning. We propose the prospects on the use of composite building materials enhanced with different volumetric fractions of...
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To promote diatom-based biofuel productions in clean energy, this paper explores the potential of using biosilica as a renewable and regenerative byproduct from diatom-based biofuel production in cementitious materials. High-purity diatomite (DE), a biosilica model compound, is selected to investigate the microstructure and durability performance o...
Article
Despite a wide range of applications, naturally occurring minerals suffer from some limitations for industrial use. Consequently, many research efforts have been conducted to develop a fast, optimized, and sustainable methodology to produce synthetic minerals. In the case of calcium silicate hydrates (CSH), the hydrothermal flow approach allows to...
Article
A complete understanding of the effect of gypsum on the C3S hydration and the role of aluminum has not been achieved. The effects of gypsum (at 2.5 wt% and 5.0 wt%) on the hydration of tricalcium silicate (C3S) and aluminum-doped C3S (Al-C3S) hydration are assessed. Isothermal calorimetry, thermodynamic modeling, XRD, TGA, and ²⁷Al and ²⁹Si MAS-NMR...
Article
The higher reactivity of orthorhombic C3A (ort-C3A) in sulfate-containing solutions, compared with cubic C3A (cb-C3A), was previously related to the differences in crystal structure or the sodium in the ort-C3A pore solution. We analyzed the hydration of cb-C3A (in water and NaOH solution) and Na-doped ort-C3A in the presence of gypsum and hemihydr...
Article
Global warming is the gradual increase in global temperatures owing to trapping of heat in the atmosphere by greenhouse gases. As of January 2020, 121 countries and 1 region, including Japan, pledged to achieve carbon neutrality by 2050. One of the measures for achieving this goal is the promotion of low-carbon urban development, which includes urb...
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Methane pyrolysis is an emerging technology to produce lower-carbon intensity hydrogen at scale, as long as the co-produced solid carbon is permanently captured. Partially replacing Portland cement with pyrolytic carbon would allow the sequestration at a scale that matches the needs of the H 2 industry. Our results suggest that compressive strength...
Article
Creep of the cement matrix affects the structural stability of concrete. In Portland cements, the creep is largely controlled by the binding phase calcium-(aluminum-)silicate-hydrate, or C-(A-)S-H. This phase has a lamellar structure and under deviatoric stress aligns its c-axis with the principal stress. However, the limiting resistance to this re...
Article
This paper presents a trans-scale finite element model based on hydraulic-thermal-mechanical coupling equations of porous medium to simulate the behavior of concrete during freezing and thawing. Unlike previous models that regard concrete as homogeneous material, this paper aims to establish a macro-size concrete model with detailed micro-structure...
Article
Nano/micro-indentation has been extensively used to examine elastic properties and creep of cement-based materials. However, there have been inconsistencies in the measured elastic moduli and debate on the creep mechanism of calcium (alumino) silicate hydrates (C-(A-)S-H). To bring new insights, we examined the deviatoric stress-induced preferred o...
Article
Understanding the silicate polymerization of calcium silicate hydrate (C-S-H) gel and its crystalline polymorphs is important in cement science. NMR can determine Si environments, but the measurement can be time-consuming and provides no spatial information. X-ray absorption near-edge structure (XANES) spectroscopy is a fast tool for probing Si coo...
Article
Calcium sulfoaluminate (CSA) cement could be a promising alternative to ordinary Portland cement (OPC) to reduce environmental impact of concrete production. This paper investigates the performance of high performance concretes produced with CSA cement in total or partial substitution of OPC (or OPC with ground granulated blast-furnace slag (GGBS))...
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The origin of different stability of crystalline calcium silicate hydrates was investigated. The tobermorite crystal has been used as an analog of cement hydrate that is being mostly manufactured material on earth. Normal tobermorite is thermally unstable and transforms to amorphous at low pressure. Meanwhile, anomalous tobermorite with high Al con...
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Polycarboxylate ether (PCE), a commonly used superplasticizer, is known to influence the morphology of ettringite during the early hydration of C3A- and ye'elimite-containing cements. According to existing theories, such morphological changes may be crucial to the expansive behavior of these cements. This paper studied the expansion of ye'elimite-a...
Article
Efforts are currently underway to improve the performance of small electric antennas and resonator-based antennas embedded in the civil infrastructure. One of the main limitations of these small antennas is that they have narrow bandwidths which limit their use when embedded in concrete. The present work shows that by changing the amount of iron (I...
Article
Roman-era concrete is the iconic embodiment of long-term physicochemical resilience. We investigated the basis of this behavior across scales of observations by coupling time-lapse (4-D) tomographic imaging of macroscopic mechanical stressing with structural microscopy and chemical spectroscopy on Roman marine concrete (RMC) from ancient harbors in...
Article
There is renewed interest in using advanced techniques to characterize ancient Roman concrete due to its exceptional durability and low-carbon footprint. In the present work, samples were drilled from the "Hospitium" in Pompeii and were analyzed by synchrotron microtomography (μCT) and neutron radiography to study how the microstructure, including...
Article
Calcium silicate hydrate (C‐S‐H), is the principal hydration product of Portland cement that mainly contributes to the physical and mechanical properties of concrete. This paper aims to investigate the three‐dimensional structure of C‐S‐H with Ca/Si ratios of 1.0 and 1.6 at the nanoscale using electron tomography. The 3D reconstructions and selecte...
Article
Debates remain on the influencing factor and long-term performance of C-S-H-seeded paste. In this study, phase-pure seeds were prepared from diluted Ca3SiO5 hydration. The seed structures were determined using synchrotron-based X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy. Nano-foils and similar Ca and O en...
Article
Tobermorite is the model for calcium aluminosilicate hydrate (C-(A-)S-H), the glue in concrete, and is also the binding phase in cement-based materials under geological conditions and in ancient Roman concrete. Correlating the mechanical properties of tobermorite with atomic structures substantially improves the understanding of C-(A-)S-H. We study...
Article
Magnesium potassium phosphate cement (MKPC) is gaining increasing popularity for specialized applications, e.g., structural rehabilitation, waste encapsulation, and 3D printing. However, the mechanical properties of struvite-K, the binding phase of MKPC, have rarely been examined. This study utilized synchrotron-based high-pressure X-ray diffractio...
Article
Nanocrystalline calcium silicate hydrate (C-S-H) is the binding phase of many low-CO2 cements. Understanding its structure-mechanical properties relationship is critical in designing sustainable concrete. For the first time, similar basal spacing (only 0.17 Å variation) of C-S-Hs at Ca/Si ratios of 0.8-1.5 are prepared via coprecipitation. The C-S-...
Article
The mechanical and thermal properties of the gigatonnes of concrete produced annually are strongly affected by the anharmonicity of the chemical bonds in its main binding phase, nanocrystalline calcium-(alumino-)silicate-hydrate (C-(A-)S-H). Improvements in C-(A-)S-H design increasingly depend on simulations utilizing a set of effective interatomic...
Article
Full-text available
X-ray Raman Scattering (XRS) is a new probe to analyze the local chemical environment of elements of interest. In this communication, XRS is, for the first time, used in the field of cement study. In situ high-pressure XRS (HP-XRS) at Ca L2,3-edge was used to examine the pressure-induced change of Ca environment of C-S-H under a loading/unloading c...
Preprint
Full-text available
There is renewed interest in using advanced techniques to characterize ancient Roman concrete. In the present work, samples were drilled from the "Hospitium" in Pompeii and were analyzed by synchrotron microtomography (uCT) and neutron radiography to study how the microstructure, including the presence of induced cracks, affects their water adsorpt...
Article
Full-text available
Calcium nitrate (CN) is used widely as an effectively inorganic setting accelerator and antifreeze admixture in concrete structures. In this paper, the multiscale investigation of CN on the hydration of C3S was studied by scanning transmission X-ray microscopy (STXM) combined with near-edge X-ray absorption fine structure (NEXAFS), 29Si MAS NMR, ca...
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Full-text available
The magnesium and sodium sulfate attacks on Portland cement paste in the presence of applied electric fields were studied, and the mineralogical alterations were investigated by both experiments and thermodynamic modeling. When an electric current flows out of the cement paste, the electric migration of ions induced sulfate ingress and decalcificat...
Article
Full-text available
Ancient Roman concrete presents exceptional durability, low-carbon footprint, and interlocking minerals that add cohesion to the final composition. Understanding of the structural characteristics of these materials using X-ray tomography (XRT) is of paramount importance in the process of designing future materials with similar complex heterogeneous...
Article
X-ray computed tomography (CT) is a non-destructive technique that offers a 3D insight into the microstructure of thick (opaque) samples with virtually no preliminary sample preparation. Since its first medical application in 1973, the technique has improved dramatically in terms of acquisition times and resolution. The best resolution achievable f...
Preprint
Roman-era concrete is the iconic embodiment of long-term physicochemical resilience. We investigated the basis of this behavior across scales of observations by coupling time-lapse (4-D) tomographic imaging of macroscopic mechanical stressing with structural microscopy and chemical spectroscopy on Roman marine concrete (RMC) from ancient harbors in...
Article
Full-text available
Progress in microstructural characterization methods is summarized. Special attention is given to advanced probes, such as X-ray imaging and spectroscopy, ¹H NMR relaxometry, in-situ and high-pressure X-ray diffraction, and digital holographic microscopy. Microtomography has become a mature technique and nanotography has improved its spatial resolu...
Article
To arrest the growth of global environmental issues, curbing the greenhouse gas emissions and primary energy consumption in concrete production is among the efficacious strategies. Cement production being the most energy- and emission-intensive activity in concrete manufacture, the partial replacement of cement clinker with supplementary cementitio...
Article
The capability of neutrons to penetrate materials opaque to other non-destructive techniques combined with relatively high neutron attenuation cross section for hydrogen provide unique possibilities to reveal internal distribution of water and other hydrogen-containing substances in various bulky samples. In this study we compare the accuracy of wa...
Article
With the aim of creating more sustainable building materials, calcium silicate hydrate (C-S-H), the primary binding phase in modern concrete, was integrated with poly(ethylene glycol) (PEG). At the crystal lattice scale, synchrotron radiation-based high-pressure X-ray diffraction (HP-XRD) reveals that the incorporation of PEG increases the ab-plana...
Article
Full-text available
Dicalcium silicate (C2S) is an important clinker mineral in Portland and belite-calcium sulfoaluminate cement. However, there is still a lack of information on the local degree of silicate polymerization and calcium coordination in C2S hydration products. This study aimed to fill this gap by characterizing the hydration of two C2S polymorphs, the β...
Article
This work reports the properties of hybrid-fiber-reinforced concrete (HyFRC) made with expansive (Type K) cement. Combinations of metallic and non-metallic fibers at total fiber volume fraction of 1% were studied. The effectiveness of double hooked-end (DHE) steel fibers in concrete containing expansive cement is investigated for the first time in...
Article
The existing macroscale models of the calcium (alumino)silicate hydrate (C-(A-)S-H), the main binder of concrete, assume that the nanocrystallites maintain random orientation under any loading conditions. However, using synchrotron-radiation-based XRD, we report the development of preferred orientation of nanocrystalline C-A-S-H, from random at amb...
Article
Calcium aluminate cement (CAC) has wide application in civil engineering and castable refractory materials. The main binding phases of hardened CAC paste, CaO·Al2O3·10H2O (CAH10), inevitably converts to 2CaO·Al2O3·8H2O (C2AH8), 3CaO·Al2O3·6H2O (C3AH6) and Al(OH)3 (AH3), leading to a significant change in the mechanical properties of the CAC matrix....
Article
Full-text available
The rheology of modern Portland cement (PC) concrete critically depends on the correct dosage of gypsum (calcium sulfate hydrate) to control the hydration of the most reactive phase - tricalcium aluminate (C3A). The underlying physio-chemical mechanism, however, remains unsolved mainly due to the lack of high-spatial-resolved and chemistry-sensitiv...
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Full-text available
The tricalcium aluminate (C₃A) and sulfate content in cement influence the hydration chemistry, setting time and rheology of cement paste, mortar and concrete. Here, in situ experiments are performed to better understand the effect of gypsum on the early hydration of cubic (cub-)C₃A and Na-doped orthorhombic (orth-)C₃A. The isothermal calorimetry d...
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Concrete is the most-used construction material worldwide. Previous studies on the environmental impacts of concrete production have mainly focused on the materials involved and energy consumption, as well as CO2 emissions; little is known, however, about its water consumption as well as the effective measures to reduce such consumption. We quantif...
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Calciuam-silicate-hydrate (C-S-H) is the principal binding phase in modern concrete. Molecular simulations imply that its nanoscale stiffness is ‘defect-driven’, i.e., dominated by crystallographic defects such as bridging site vacancies in its silicate chains. However, experimental validation of this result is difficult due to the hierarchically p...
Article
This paper presents an experimental study that investigates the influence of the low fiber content of polypropylene and hooked-end steel fibers on the properties of high-strength concrete. The study variables include fiber types and fiber contents. The effect of combining both fibers with a total fiber content of 1.0% was also studied in some mixtu...
Article
Full-text available
Small resonator antennas, such as metaresonator antennas, have narrow bandwidths, which limits their effective range of frequencies. When they are used as embedded antennas in building materials, their performance is affected more than other types of antennas, as typical building materials have a shielding effectiveness (SE) of 80 dB to 100 dB. Add...
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Full-text available
Properties of organic/inorganic composites can be highly dependent on the interfacial connections. In this work, molecular dynamics, using pair potential based force fields, was employed to investigate the structure, dynamics and stability of interfacial connections between calcium silicate hydrates (C-S-H) and organic functional groups of three di...
Article
Full-text available
Calcium (alumino)silicate hydrate (C–(A–)S–H) is the critical binding phase in modern Portland cement-based concrete, yet the relationship between its structure and stoichiometry is not completely understood. In this study, Raman spectroscopy is used to analyze the effects of varying Ca/Si molar ratio (0.6–1.6), Al/Si molar ratio (0.0–0.1), and syn...
Article
This paper presents a solution chemistry-focused analysis of orthorhombic and cubic tricalcium aluminate (orth-C3A and cub-C3A, respectively) hydration. It is shown that the different solubilities of cub- and orth-C3A influence the bulk aqueous Ca to Al concentration ratio and the C3A/solution interface chemistry. The results are consistent with th...
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Full-text available
This paper presents research on the influence of quartz deformation in aggregates for the development of the alkali-silica reaction in concrete and its relationship with silica dissolution. The study also compares these characteristics with the field behavior of such rocks in concrete. The paper proposes parameters to classify the different degrees...
Article
Paulo J. M. Monteiro, Sabbie A. Miller and Arpad Horvath provide an overview of the challenges and accomplishments in reducing the environmental burden of concrete production.
Article
The main binding phases of calcium aluminate cement (CAC) concrete, CaO∙Al2O3∙10H2O (CAH10) and 2CaO∙Al2O3∙8H2O (C2AH8), slowly convert to 3CaO∙Al2O3∙6H2O (C3AH6) and Al(OH)3 (AH3). This reaction significantly speeds up at a temperature higher than ~30°C, and over time leads to significant strength loss in concrete. Due to the lack of direct eviden...
Article
Tricalcium aluminate (cement clinker phase), gypsum, katoite, ettringite, and calcium mono-sulfoaluminate hydrate (abbreviated as kuzelite) are the major minerals in the hydration reaction of tricalcium aluminate in the presence of gypsum and have critical impacts on the kinetics and thermodynamics of early-age cement hydration mechanisms. Here, sp...
Article
Major developments in concrete technology have been achieved with the use of polycarboxylate-based superplasticizers (PCEs) to improve the concrete rheology without increasing the mix water content. Currently, it is possible to control the fluidity of the fresh concrete and obtain stronger and more durable structures. Therefore, there is a strong i...