Olivér Fenyvesi

• PhD
• Professor (Assistant) at Budapest University of Technology and Economics

The objective of this research is to develop an innovative methodology for evaluating the quality of coarse aggregate mixes that incorporate recycled concrete aggregate for use in structural concrete. The proposed approach consists of three steps: measuring the packing density, quantifying the adhered mortar, and characterizing the mechanical resis...

This paper aims to raise awareness regarding the obstacles limiting alkali-activated binders’ (AABs) application as a sustainable solution in the construction industry. Such an evaluation is essential in this industry, which has been introducing a wide range of alternatives to cement binders yet achieved limited utilisation. It has been recognised...

One of the sustainable solutions for cementitious materials could be the inclusion of locally available raw materials with possible lower environmental and/or economic impacts that meet technical requirements. This study focuses on waste perlite and recycled concrete powders, which are wastes from natural or artificial rock. Their effects on harden...

An empirical model was developed to estimate the thermal conductivity of heat-treated straw bulks based on laboratory experiments. During the measurements, two different types of straw were investigated, barley and wheat. Barley was used to composing our empirical model and define the influencing model parameters, and wheat straw was used for valid...

For sustainable thermal insulations, vegetable fibers/stems are widely used, which have very dispersed material properties even within a variety. The examination of the fibers’ porosity in the conventional way provided reference values in this study, but it can be problematic for cellulose-based fibers. This study examines the porosity of two straw...

There have been numerous researches focusing on the alternatives to conventional concrete regarding environmental benefits and trade-offs. For this purpose, nowadays, the Life Cycle Assessment (LCA) is widely used. Until now, LCA results of conventional and green concretes have shown some limitations, and this paper focuses on addressing them. Firs...

About half of the concrete is occupied by coarse aggregate. When as aggregate weak raw material is used, there is a possibility of the formation of local cracks during the loading of the concrete. Since recycled concrete aggregate comprises both adhered old mortar and natural aggregate it is expected that its resistance to crushing would be importa...

An analytic-empirical model was developed to describe the heat transfer process in raw straw bulks based on laboratory experiments for calculating the thermal performance of straw-based walls and thermal insulations. During the tests, two different types of straw were investigated. The first was barley, which we used to compose our model and identi...

Kötött és kötetlen szalmaszál halmazok kezelési ciklusszámának hatása a halmazok hővezetésére és felületi tulajdonságira Effect of the number of treatment cycles on the thermal conductivity and surface properties of bonded and unbounded straw fibre bulks Dr. FENYVESI Olivér, adjunktus 1

Most of the thermal insulations in the construction industry market based on fossil raw material or need a huge amount of production energy. Nowadays, sustainable thermal insulation products are more popular, and the demand for these products on the market is increasing. Some of them reach the main material properties of artificial ones but usually...

In the next decades many buildings and structures, constructed from autoclaved aerated concrete (AAC) will reach their end of lifetime, therefore solutions should be developed to recycle the resulting waste material. AAC blocks cannot be reused in the form of building blocks as traditional clay bricks. The typical form of AAC waste is crushed stone...

Nowadays huge amount of thermal insulation materials have to be produced. Materials with high performance have high price, and the most popular thermal insulations have large environmental footprint and these are not able to biodegradation and their production needs high energy investment [1, 2]. One alternative the use of natural based biodegradab...

EU laws have been the most effective driving force of Latvian and Hungarian environmental legislation in order to improve recycling of packaging waste. In Latvia and Hungary the waste diversion strategies have focused on establishing treatment capacity and setting up schemes for separate collection, which largely cover packaging waste. Despite all...

Concrete is often sensitive to cracking, which could be the result of early age shrinkage. Cracks can cause the corrosion of steel reinforcements and reduce the lifetime of concrete structures. Altogether crack tendency of concrete can be influenced by many parameters in the concrete mixture. Laboratory tests have been carried out according to the...

Freeze-thaw testing methods with different grade of severity have been applied to investigate the durability of – intentionally non air entrained – fibre reinforced concretes (FRC) mixed with nominally zero, 25, 50 and 75 kg/m3cold drawn steel fibres (30/0.5 mm). Concrete specimens were made with sulphate resistant Portland cement and were stored 2...

Conventional steel reinforced concrete is often sensitive to cracking, and these cracks could be the result of early age shrinkage. Cracks can cause the corrosion of steel reinforcements reducing the lifetime of concrete structures. To reduce this problem fibre reinforced concrete (FRC) is one possible solution. Laboratory tests have been carried o...