(1 - 20 of 21)

Pages

document
Souza, L.M.S. (author), Polder, R.B. (author), Çopuroğlu, O. (author)
Alkali–silica reaction (ASR) affects numerous concrete structures worldwide. However, the intervention options for ASR in existing structures are limited. Lithium is proposed to suppress expansion. In this paper, an investigation on two-chamber lithium migration as treatment against ASR is presented. First, the influence of different levels of...
article 2017
document
Polder, R.B. (author), TNO Bouw (author)
Cathodic protection (CP) of reinforcing steel in concrete structures has been used successfully for over 20 years. CP is able to stop corrosion in a reliable and economical way where chloride contamination has caused reinforcement corrosion and subsequent concrete damage. To new structures where corrosion is anticipated, cathodic prevention can...
article 1998
document
Pacheco, J. (author), Polder, R.B. (author)
Chloride induced reinforcement corrosion is the predominant degradation mechanism
article 2016
document
de Vries, J. (author), Polder, R.B. (author)
As part of the maintenance policy of the Dutch Ministry of Transport, Civil Engineering Division, hydrophobic treatment of concrete was considered as an additional protective measure against penetration of aggressive substances, for instance deicing salts in bridge decks. A set of tests was designed to determine the performance of commercially...
article 1996
document
Pereira, L.F. (author), Weerheijm, J. (author), Sluys, L.J. (author)
The development of realistic numerical tools to efficiently model the response of concrete structures subjected to close-in detonations and high velocity impact has been one of the major quests in defense research. Under these loading conditions, quasi-brittle materials undergo a multitude of failure (damage) mechanisms. Dynamic tensile failure ...
article 2016
document
Larbi, J.A. (author), Heijnen, W.M.M. (author), TNO Bouw (author)
This article presents the results of a microscopic analysis to determine the cement content of five samples of hardened concrete prepared with portland pozzolanic cement and crushed limestone as part of the aggregate. The volume fraction of the coarse aggregate was determined macroscopically from polished plates of the concrete samples. The...
article 1997
document
Polder, R.B. (author), TNO Bouw (author)
Chloride penetration from sea water may cause corrosion of reinforcement in concrete structures. Adding reactive inorganic materials such as blast furnace slag, fly ash or silica fume to the cement matrix improves the resistance against chloride penetration as compared to Portland cement concrete. A relatively simple laboratory procedure was...
article 1996
document
Caspeele, R. (author), Sykora, M. (author), Allaix, D.L. (author), Steenbergen, R.D.J.M. (author)
In contrast to the design of new structures, the assessment of existing structures often relies on the subjective judgement of the investigating engineer. An objective verification format for existing structures based on alternative partial factors is however feasible, enabling a rather simple and straightforward, but objective and coherent...
article 2013
document
Yang, Z. (author), Polder, R. (author), Mol, J.M.C. (author)
Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active corrosion protective component of reinforced concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were tested both in alkaline solution and mortar for...
article 2017
document
Lu, Y. (author), Xu, J. (author), Weerheijm, J. (author)
This paper presents a numerical modelling study on the simulation of the cracking process and fracture energy in concrete under high strain rate. To capture the stress wave effect and the damage evolution at the meso-length scale, both a homogeneous model with a millimetre-resolution mesh and an explicit heterogeneous mesoscale model with random...
conference paper 2013
document
de Vries, J. (author), Polder, R.B. (author), Borsje, H. (author), TNO Bouw (author)
The subject of this study was the performance of hydrophobic treatment to protect concrete against chloride penetration from de-icing salts. Hydrophobic treatment makes a concrete surface absorb less water and less chloride. Several types of tests were carried out to study the performance of hydrophobised concrete. Salt ponding/drying tests...
conference paper 1998
document
Polder, R.B. (author), Bakker, J.D. (author), Postema, F.J. (author), TNO Bouw (author)
As a case study, the cost of applying cathodic protection (CP) to the columns and beams supporting two bridges was compared to the cost of replacement (due to reinforcement corrosion). All costs during the service life of the CP system were considered: initial cost, annual checks, maintenance of anode systems and specialist supervision. It was...
conference paper 1998
document
Polder, R.B. (author), Nerland, O.C. (author), TNO Bouw (author)
An experimental study of cathodic protection (CP) was carried out with a conductive primer anode applied to specimens from a concrete bridge. The bridge was demolished after 30 years of service due to severe delaminations and reinforcement corrosion. Four specimens of approximately 1 m2 each were made and characterised by steel potential,...
conference paper 1998
document
Varas, J.M. (author), Soetens, F. (author)
The effect of a blast explosion on a typical steel frame building is investigated by means of computer simulations. The simulations help to identify possible hot spots that may lead to local or global failure. The blast energy is transferred to the structure by means of the façade. In particular attention is paid to the modelling of the façade...
conference paper 2010
document
Polder, R.B. (author), de Vries, H. (author), TNO Bouw (author)
Penetration of de-icing salts into concrete bridge decks may cause corrosion of reinforcement. Hydrophobic treatment of concrete was studied as additional protection. It was shown that hydrophobic treatment strongly reduces chloride ingress, during semi-permanent contact and in wetting/drying situations. The protection remains effective for at...
conference paper 1999
document
Ožbolt, J. (author), Weerheijm, J. (author), Sharma, A. (author)
The behavior of concrete structures is strongly influenced by the loading rate. Compared to quasi-static loading, on meso and macro-scale concrete loaded by impact loading acts in a different way. First, there is a strain-rate influence on strength, stiffness, ductility, and, second, there are inertia forces activated which influence the...
conference paper 2013
document
Siemes, A.J.M. (author), TNO Bouw (author)
After the introduction of reinforced concrete it was believed that the material was extremely durable. Soon it was found that reinforced concrete could have serious durability problems and that special care should be taken to avoid them. Durability became a design issue.
conference paper 2002
document
de Vries, J. (author), Polder, R.B. (author), Borsje, H. (author)
Hydrophobic treatment makes a concrete surface absorb less water and less chloride. Hydrophobic treatment was studied as a protection agninst chloride penetration from deicing salts. Test methods were designed. Nine hydrophobic products were tested, of which three complied to the requirements on finished concrete surfaces. The water absorption...
conference paper 1996
document
Rossi, E. (author), Nijland, T.G. (author), Copuroglu, O. (author), Polder, R.B. (author), Savija, B. (author)
Although corrosion of reinforcement is a well-known issue for the construction industry, there are still open questions about some fundamentals of corrosion in reinforced concrete. These points include, among others, which are the most sensitive locations of the steel/concrete interface for pitting corrosion to initiate and to propagate. In this...
conference paper 2019
document
Polder, R.B. (author)
This paper describes methods to assess concrete resistivity on site for various purposes related to corrosion and protection of reinforcement. It is based on a first draft of a RILEM Technical Recommendation. The electrical resistivity of concrete can be related to the two processes involved in corrosion of reinforcement: initiation (chloride...
conference paper 2000
(1 - 20 of 21)

Pages