Roman Loser

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Carbonation resistance of mortar produced with alternative cements

Andreas Leemann, Hanna Pahlke, Roman Loser, Frank Winnefeld

Materials and Structures > 2018 > 51 > 5 > 1-12

The use of alternative cements with lower CO₂ emissions during production compared to ordinary Portland cement (PC) is only sustainable, if the durability and with it the service life of components and structures produced with them are not compromised. In this project, the carbonation resistance of mortars produced with calcium sulfoaluminate cement (CSA) and three different slag-based cements is...

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Steady-state O₂ and CO₂ diffusion in carbonated mortars produced with blended cements

Andreas Leemann, Roman Loser, Beat Münch, Pietro Lura

Materials and Structures > 2017 > 50 > 6 > 1-7

The diffusion coefficient $$D_{{{\text{O}}_{2} }}$$ D O 2 , the porosity and the pore structure of mortars produced with a Portland cement and a range of blended cements containing limestone powder, microsilica, portlandite or slag were measured in the non-carbonated and the carbonated state. Additionally, the setup for measuring O₂ diffusion was adapted to measure also the CO₂ diffusion...

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An accelerated sulfate resistance test for concrete

Roman Loser, Andreas Leemann

Materials and Structures > 2016 > 49 > 8 > 3445-3457

The sulfate resistance of concrete was tested using drying-immersion cycles of varying duration in different sulfate solutions. The measured expansion in the different protocols showed a correlation to the sulfate profiles in the test specimens determined by EDX. Based on the magnitude of expansion and the test duration, a suitable protocol for testing job-site concrete was identified. A matrix of...

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Relation between carbonation resistance, mix design and exposure of mortar and concrete

Andreas Leemann, Peter Nygaard, Josef Kaufmann, Roman Loser

Cement and Concrete Composites > 2015 > 62 > Complete > 33-43

When cement with mineral additions is employed, the carbonation resistance of mortar and concrete may be decreased. In this study, mortars containing mineral additions are exposed both to accelerated carbonation (1% and 4% CO₂) and to natural carbonation. Additionally, concrete mixtures produced with different cements, water-to-cement ratios and paste volumes are exposed to natural carbonation. The...

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An inter lab comparison of gas transport testing procedures: Oxygen permeability and oxygen diffusivity

Chiara Villani, Roman Loser, Martine J. West, Carmelo Di Bella, more

Cement and Concrete Composites > 2014 > 53 > C > 357-366

The transport properties of concrete are useful measurements as they can provide a potential indication of durability and can be used in the prediction of the service life of concrete elements. Gas permeability and diffusivity test methods are attractive due to the ease of testing, their non-destructive nature and their potential to correlate to in-field carbonation of reinforced concrete structures...

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Shrinkage and creep of SCC – The influence of paste volume and binder composition

Andreas Leemann, Pietro Lura, Roman Loser

Construction and Building Materials > 2011 > 25 > 5 > 2283-2289

In this study, the stress–strain-behaviour of self-compacting concrete (SCC) and conventionally vibrated concrete (CVC) is compared. The influence of the paste volume and the cement type on E-modulus, flexural and compressive strengths, drying shrinkage, creep and stress development under restrained conditions is investigated on three SCC mixtures and three mixtures of CVC with identical water-to-cement-ratio...

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Investigation into the mechanisms leading to explosion of pétanque balls

Roman Loser, Gabor Piskoty, Andrea Al-Badri, Martin Tuchschmid, more

Engineering Failure Analysis > 2011 > 18 > 2 > 633-648

Pétanque is a game originating in Provence, France, which has become common in many European countries. It is played using balls with a diameter of 70–80mm and a weight of 650–800g. The weight can either be adjusted by the thickness of the metallic shell or, mainly in case of cheap balls, by a filling. Pétanque balls are commonly available at supermarkets.After an explosion of a pétanque ball stored...

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A volumetric technique for measuring the coefficient of thermal expansion of hardening cement paste and mortar

Roman Loser, Beat Münch, Pietro Lura

Cement and Concrete Research > 2010 > 40 > 7 > 1138-1147

Knowledge of the coefficient of thermal expansion (CTE) is of paramount importance for the determination of the cracking risk of concrete structures at early ages. This paper presents a novel technique which is suitable to measure the CTE of hardening materials with high accuracy starting from casting time.The technique consists of casting a small amount of cement paste or mortar into flexible membranes...

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Influence of cement type on ITZ porosity and chloride resistance of self-compacting concrete

Andreas Leemann, Roman Loser, Beat Münch

Cement and Concrete Composites > 2010 > 32 > 2 > 116-120

With the increasing use of self-compacting concrete (SCC) its durability has come into focus. Concerning the microstructure of concrete, the porosity in the interfacial transition zone (ITZ) is regarded as a key feature for permeability and durability. Generally, a combination of cement and mineral admixtures is used for the production of SCC. In the present study, ITZ porosity of four SCC mixtures...

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Chloride resistance of concrete and its binding capacity – Comparison between experimental results and thermodynamic modeling

Roman Loser, Barbara Lothenbach, Andreas Leemann, Martin Tuchschmid

Cement and Concrete Composites > 2010 > 32 > 1 > 34-42

The chloride resistance of concrete mixtures produced with different binders and water-to-binder ratios is determined by three different methods (natural chloride diffusion, accelerated chloride migration and conductivity measurement). The influence of mix design and type of binder are evaluated and related to porosity. The effect of chloride binding on chloride resistance is assessed by thermodynamic...

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Analysis of cement-bonded materials by multi-cycle mercury intrusion and nitrogen sorption

Josef Kaufmann, Roman Loser, Andreas Leemann

Journal of Colloid And Interface Science > 2009 > 336 > 2 > 730-737

The pore systems of cement-based materials are studied by N ₂ sorption and mercury intrusion porosimetry (MIP). Pore size distributions and internal surfaces are derived. Especially in materials with a broad pore size distribution, these (and other) methods generally do not lead to coincident results. It is shown here, how the interpretation of the experimental data of the two methods may...

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Detection of chlorides and moisture in concrete structures with ground penetrating radar

Johannes Hugenschmidt, Roman Loser

Materials and Structures > 2008 > 41 > 4 > 785-792

Corrosion of re-bar within reinforced concrete is a major problem in countries where salt is applied to roads for de-icing. Concrete structures are periodically inspected in order to monitor possible damage caused by chloride induced corrosion of the reinforcement. However, bridge decks covered with asphalt pavements are not accessible for visual inspection and probing is limited. As a result, the...

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Search results for: Roman Loser

Carbonation resistance of mortar produced with alternative cements

Steady-state O₂ and CO₂ diffusion in carbonated mortars produced with blended cements

An accelerated sulfate resistance test for concrete

Relation between carbonation resistance, mix design and exposure of mortar and concrete

An inter lab comparison of gas transport testing procedures: Oxygen permeability and oxygen diffusivity

Shrinkage and creep of SCC – The influence of paste volume and binder composition

Investigation into the mechanisms leading to explosion of pétanque balls

A volumetric technique for measuring the coefficient of thermal expansion of hardening cement paste and mortar

Influence of cement type on ITZ porosity and chloride resistance of self-compacting concrete

Chloride resistance of concrete and its binding capacity – Comparison between experimental results and thermodynamic modeling

Analysis of cement-bonded materials by multi-cycle mercury intrusion and nitrogen sorption

Detection of chlorides and moisture in concrete structures with ground penetrating radar

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