Salem Georges Nehme

Budapest University of Technology and Economics · Department of Construction Materials and Technology

This paper assesses the feasibility of concrete mixtures containing high replacement rates of fine and/or coarse waste brick aggregates. Three mixture series prepared with different water-to-cement ratios are tested for workability, compressive strength, split tensile strength, modulus of elasticity, water permeability (by capillary or under pressu...

The frost resistance of concrete is important for all structures where freezing and thawing are cyclically occurring, such as bridges and infrastructure. Understanding the effects of freeze-thaw cycles and monitoring their consequences has been a challenge for both researchers and standard committees for many decades. Within the framework of a Hung...

Due to the construction of underground structures and hazardous waste storages, understanding and modelling of water flow through concrete has become a major topic for life-span analyses. The water retention curve (WRC) is an essential unsaturated soil function, which can be determined not only for soil samples, but also for other porous media. Thi...

The temperature rise in mass concrete usually leads to premature distresses and early-age cracking. This paper correlates the time-temperature profiles to the mechanical properties and durability of high-performance mass concrete (HPMC). Five types of cement having different specific surface areas (SSA) and granulated blast furnace slag (GBFS) repl...

Ultra-high performance concrete (UHPC) mixtures are typically proportioned using high binder content and low water-to-binder ratio (w/b). Yet, in most cases, such recipes denote the presence of unhydrated cement and other pozzolanic materials, thus playing the role of costly fillers in the matrix. Two UHPC categories proportioned with two cement ty...

A 2001. szeptember 11-i terrortámadás óta a kiemelt építményeket megnövekedett biztonsági elvárások mellett szükséges tervezni. Ez az előírás az újonnan épített nukleáris létesítményekre, köztük a Paks II. atomerőmű-beruházásra is vonatkozik. Ezen megnövekedett biztonsági igények meghatározzák, hogy a tervezett atomerőmű konténmentjének ellen kell...

A fenntarthatóság szempontjából rendkívül fontos a károsanyag kibocsájtás csökkentése, a meglévő anyagok hosszú időn át tartó használata és az élettartamuk végén az újrahasznosításuk. Egyre jelentősebb a törekvés, hogy a betonok anyagában növeljük a hulladékok és ipari melléktermékek mennyiségét, és csökkentsük a cementtartalmat és a bányászott vag...

A 2001. szeptember 11-i terrortámadás óta a kiemelt építményeket megnövekedett biztonsági elvárások mellett szükséges tervezni. Ez az előírás az újonnan épített nukleáris létesítményekre, köztük a Paks II. atomerőmű-beruházásra is vonatkozik. Ezen megnövekedett biztonsági igények meghatározzák, hogy a tervezett atomerőmű konténmentjének ellen kell...

The bond-slip relationship between concrete and steel is significant in evaluating the nonlinear behavior of reinforced concrete structures. The force transmitted by the bond in reinforced concrete structures was studied numerically in high-strength, lightweight concrete with ribbed reinforcing steel bar or seven-wire strand, using ATENA 3D softwar...

A betonok fagy-, illetve fagy- és olvasztósóállóság-vizsgálati hámlása időben lejátszódó folyamat, amely lassuló vagy gyorsuló jellegének korábban nem túl sok figyelmet szenteltünk. A hámlasztásos fagyasztási lassulás is viszonylag új fogalomnak tekinthető, amely fogalom ilyen elnevezésének a nemzetközi irodalomban sem találtuk a nyomát. E cikkben...

Due to the construction of underground structures and hazardous waste storages, understanding and modelling of water flow through concrete has become a major topic for life-span analyses. The water retention curve (WRC) is an essential unsaturated soil function, which can be determined not only for soil samples, but also for other porous media. Thi...

erlite is a natural glassy volcanic rock used in construction applications requiring improved lightweight, thermal, and acoustic properties. During processing of raw perlite (i.e., cutting and fractioning to different sizes), large amounts of powders are collected and stored as waste materials. This paper evaluates the effect of waste perlite (WP)...

A 3D nyomtatás a megjelenésétől fogva az érdeklődés középpontjában van. A technológia fejlődésén és sikeres alkalmazásain keresztül életünk részévé vált a legkülönbözőbb területeken. A folyamatok összetettsége révén a betonnyomtatás van talán a többi területhez képest (műanyagnyomtatás és fémnyomtatás) leginkább lemaradva. Szándékunk ezért részlete...

Due to the construction of underground structures and hazardous waste storages, understanding and modelling of seepage in concrete has become an important issue in life-span analyses. This study deals with the estimation of unsaturated permeability function for different concrete mixtures using the theory of water retention curve. The WRC is an ess...

The present study experimentally investigated the impact of incorporating unprocessed waste fly ash (UWFA) on the residual mechanical properties of self-compacting concrete (SCC) after exposure to elevated temperature. Three mixtures of SCC have been produced by replacing the cement mass by 0%, 15% and 30% of UWFA. Generally, the fire resistance of...

A megszilárdult betonnal, betontermékkel, vasbeton és feszített vasbeton szerkezeti elemmel érintkező lágyvizek és agresszív vizek, folyadékok, gázok, gőzök, permetek, erjedő anyagok a cement kötőanyagú betonok oldódásos korrózióját okozhatják. Cikksorozatunknak e folyóirat 2017. évi 3. számában megjelent 1. részében (Balázs et al., 2017) a vizek é...

Due to the construction of underground structures and hazardous waste storages, understanding and modelling of seepage in concrete has become an important issue in life-span analyses. The theories and calculation methods of unsaturated soil mechanics provide an opportunity to analyze water flow in other types of porous media (e.g. concrete) as well...

Due to the construction of underground structures and hazardous waste storages, understanding and modelling of water flow through concrete has become a major topic for life-span analyses. The water re-tention curve is an essential unsaturated soil function, which can be determined not only for soil samples, but also for other porous media. This stu...

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Self-compacting concrete (SCC) is characterized by unique workability properties. Stagnation or segregation of SCC must be avoided to obtain a homogenous and stable mixture. When SCC is produced, it is essential that the concrete has all the adequate fresh properties at the time of placement. For a successful and reliable application of SCC, the pr...

Self-compacting concrete has gained a wide range of applications as a result of its unique properties, which can offer high strength and durable type of concrete with the proper selection of the raw materials. The purpose of this study was to show the effect of the use of high dosage of air entraining admixture on the properties of self-compacting...

The design methods of the load bearing glass columns developed extremely in the last years. Numerous glass researchers have been trying to optimize the glass structures in terms of cost-effectiveness and safety. The authors carried out several laboratory experiments to analyze the key factors of the glass column design. Factors are investigated in...

Self-compacting concrete (SCC) is becoming more popular in terms of application and innovation in the building industry. Durable concrete structures can be established when SCC is used with the proper mix design and selection of materials. The amount and type of filler or supplementary cementitious materilas (SCMs) are among the most important para...

M egyetem rkp 3. Main building I. floor 85. SUMMARY This study aims to investigate the effect of maximum aggregate size (d max) on the mechanical properties of high-strength concrete (HSC). The constant parameters were the following: Shrinkage reducing admixture (SRA) to cement weight ratio (1.5%), metakaolin to cement weight ratio (10%), silica fu...

Evaluation of the applicability and efficiency of different cement types and maximum aggregate sizes on the hardened properties of high strength concrete propertied with different paste volumes along with the addition of supplementary cementitious materials

Different stages in the production of expanded perlite provide various types of waste by-products that could be used in the building industry, thus supporting a sustainable environment. In this study, the use of waste perlite powder (WPP) at a high content as a filler material in self-compacting concrete (SCC) was investigated. The combination of b...

This experimental work aims to study the mechanical response of the steel fiber reinforced self-compacting concrete (SFR-SCC) panels. To do so, the rheological and mechanical characteristics of SFR-SCC mixtures were evaluated. Slump flow diameter and V-funnel flow time tests were determined at the fresh stage. The compressive strength, and the maxi...

Minimizing the production energy and resources consumption are the key principle for engineering sustainability. In the case of concrete structures, this concept can be achieved by the use of materials in the most efficient way considering in the mix design the optimal mechanical and durability properties. The substitution of ordinary Portland ceme...

This paper investigates the effect of supplementary cementitious materials (SCMs) metakaolin (MK) and silica fume (SF) on the mechanical properties of ultra-high performance concretes (UHPC). Varying water- binder ratio, and setting the constant parameters as water-cement ratio and cement weight replacement by MK and SF, a total of eight UHPC were...

Az utóbbi évtizedekben számos épületkatasztrófa igazolta, hogy a tűzteherre való méretezés kérdései továbbra is aktuálisak. A különböző hőmérsékleti tartományokban a betonban lejátszódó legfontosabb fizikai és kémiai folyamatok jelentősen befolyásolják a beton magas hőmérséklet hatására kialakuló anyagtulajdonságait. A beton tűzterhelés hatására be...

The application of glass as a modern material in construction field is highly desirable in comparison with other construction materials due to aesthetic purposes. There is a high demand of official standards that meet the industry requirements. Laboratory experiments were carried out to understand the stability issues of glass columns. The glass sp...

Existing bond models for FRP reinforcements are based on limited number of parameters only. Present study includes the description of an extensive experimental work, as well as an analytical part for modelling the bond behaviour of FRP rebars in plain and in fibre-reinforced concrete. Experimental parameters consisted of: (1) type of FRP rebar (car...

Diagnostic of concrete structure properties is essential towards assessing the properties of the evaluated element. Since the Schmidt hammer is categorized as an economic and effective non-destructive testing tool, an extensive investigation is applied on several hundred of concrete specimens produced from several types, in order to assess the comp...

There is a growing interest in non-destructive testing of cement based materials in the construction industry, especially when it comes to high performance concretes. In this paper, the compressive strength of 2 concrete types, normally vibrated concrete (NVC) and self-compacting concrete (SCC), is evaluated by ultrasonic pulse velocity (UPV) non-d...

With the progress in self compacting concrete (SCC) application coupled with obligations for shorter construction periods, there is a necessity for further evaluation regarding applicability of predictive equations connected to mechanical properties. This research investigated the effect of air entrained admixtures on the mechanical response of SCC...

The present paper focuses on interesting features influencing the behavior of self-compacting concrete in terms of its related properties. Based on selected peer reviewed and non-peer reviewed conference articles, authors briefly highlight exciting recent developments and changes influencing SCC properties. Information was collected from the eighth...

Service life and durability are interconnected towards keeping the structure behaviour and integrity safe and adequate. The research consist of applying the experimental results of rapid chloride migration (RCM) coefficient in a probabilistic deterioration model. Chloride penetration is modelled using Fick’s diffusion law. Through this time depende...

The application of glass as a modern material in construction field is highly desirable in comparison with other materials such as wood, steel or the reinforced concrete due to aesthetic purposes. Hence there is a high demand of official standards that meet the industry requirements. Glass recommendations which define the function of the materials...

In order to obtain an adequate pore structure in self-compacting concrete (SCC), durability indicators must be studied and analyzed to reach an optimized SCC mixture. A comparative study between non air-entrained and air-entrained SCC, containing metakaolin (MK) and silica fume (SF) with respect to reference mixtures is conducted. The objective of...

Nowadays supporting structures can be transparent due to the development of glass strengthening procedures. The building glass as a versatile building material enables the efforts of the architects due to its transparency. This paper focuses on glass columns in the topic of load-bearing glasses and also on the design and load bearing capacity of fi...

High-strength concrete (HSC) and ultra-high strength concrete (UHSC) have become today highly required due to their enhanced properties in terms of strength and durability. An experimental program was executed at BME, Department of Construction Materials and Technologies in order to evaluate the mechanical properties of HSC and UHSC mixtures includ...

There is a growing interest in non-destructive testing of cement based materials in the construction industry, especially when it comes to high performance concretes. In this paper, the compressive strength of 2 concrete types, normally vibrated concrete (NVC) and self-compacting concrete (SCC), is evaluated by ultrasonic pulse velocity (UPV) non-d...

An application of accelerated carbonation experiment was executed in which the assessment of carbonation depth of several types of concrete mixtures were performed. Under a controlled environment, emission of CO 2 gas was provided. Carbonation depth and surface hardness of concrete are directly related in case of performing Nondestructive tests (ND...

Durability, safety and performance are the target today in structure assessment for a reliable diagnostic method. The development of Self-compacting concrete (SCC) is increasing gradually to fulfil many aspects of construction industry. Therefore, durability properties still need some enhancements particularly in term of microstructure properties....

Durability, safety and performance are the target today in structure assessment for a reliable diagnostic method. The development of Self-compacting concrete (SCC) is increasing gradually to fulfil many aspects of construction industry. Therefore, durability properties still need some enhancements particularly in term of microstructure properties....

The construction industry demands more durable concrete with high performance. Self-compacting concrete (SCC) is developing gradually to meet many aspects of construction technology, especially reinforced concrete. On the other hand, durability properties still need some enhancements particularly in term of microstructure properties. Furthermore, t...

The construction industry demands more durable concrete with high performance. Self-compacting concrete (SCC) is developing gradually to meet many aspects of construction technology, especially reinforced concrete. On the other hand, durability properties still need some enhancements particularly in term of microstructure properties. Furthermore, t...

The aim of the paper is to define the thermal properties (thermal conductivity, density and specific heat capacity) of steel, plastic and glass fiber reinforced concretes that are widely used for industrial floors, and to determine equivalent concrete thermal conductivity values for numerical thermal modelling of steel fibre reinforced concretes. I...

As a result of the demand for special concrete and the claim for aesthetics of reinforced concrete construction as well as new concreting procedures, concrete was made economical and multi-faceted. The up-todate concrete technology and the modern admixture makes high performance and high durability concrete realisation possible. High early strength...

Concrete imposes a significant effect on the environment due to the production of its components. Hence the direction today is targeted towards construction demolition waste and the methodology of enhancing the quality and quantity of recycled aggregates. This paper evaluates the implementation of crushed brick as coarse and fine aggregate as a rep...

The appearing of the modern glass façade system was a high step development in the façade planning. However the used steel surfaces is constantly reducing in the last decades. Nowadays the facades consist fast glass material and only a little part is the steel. The safety is important in every building materials especially glass materials. Laborato...

The construction industry demands more durable concrete with high performance. Self-compacting concrete (SCC) is developing gradually to meet many aspects of construction technology, especially reinforced concrete. On the other hand, durability properties still need some enhancements particularly in term of microstructure properties. Furthermore, t...

Supporting structures can be transparent nowadays due to the development of glass strengthening procedures. The building glass as a versatile building material supports architectural design due to its transparency. The paper focuses on load-bearing glass columns and also on the design, the load bearing capacity and the stability issues of fins. Int...

The authors demonstrated in a separate paper [1] the buckling behaviour of load-bearing glass columns and also the load bearing capacity issues of glass fins based on laboratory experiments. Present paper focuses on load-bearing glass columns and the stability issues of glass fins based on existing calculation methods of the critical load of glass...

Concrete is the most widely used construction material in the world. [1,2] Recycled materials are used both as aggregates to concrete (recycled concrete aggregate) and to layer of roads. • Recycling factor: The amount of pre- and/or post-consumer material used to manufacture a recycled product (expressed as a percentage of the total content). • Rec...

Nowadays the demand for concrete with high quality is permanent. The claim to build aesthetic reinforced concrete structures is increasing. In the last decade the development of the new concreting procedures became faster, therefore the concrete was further developed to be economical and multi-faceted. The self-compacting concrete has widespread us...

The composition and structure of hardened cement paste have an important influence on the properties of concrete exposed to high temperatures. In case of UHPC the application of silica fume is often necessary. Characteristics of concrete during and after the heating process depend mainly on: the type of cement, the type of aggregate and the interac...

The aim of the research was to characterize the concrete mixtures for spun-cast concrete and to determine the relationship between the compacting ratio and the manner of segregation. In the research 23 specimens of 9 different mixtures with low w/c ratio were tested. Investigated parameters included w/c, spinning speed, duration, and properties of...