I am pleased to have been given the opportunity to welcome you to the November issue of Construction Materials, a journal which is recognised as making an increasing contribution to the worldwide knowledge of materials used in the construction and engineering industries.
Much of this issue concerns concrete or concrete-related matters and whilst papers dealing with the advancement of other materials are to be welcomed, it is not unexpected that concrete features so heavily being such a widely-used material throughout the world for structural and architectural applications, both for in-situ work and prefabricated systems. It is interesting that there is such drive to advance current methods and utilise sources of untapped raw materials particularly in the field of concrete technology.
This issue starts with a briefing by Pilbeam and Barfield (2010) which concerns a cladding material certain to attract the attention of the architectural profession. The current trend for distinctive and sometimes colourful façade systems for buildings in the UK has created a demand for products of this kind. The material is described as having environmental benefits and will hopefully meet the demanding commercial requirements of this market sector.
The second briefing by Davies (2010) concerns chemical emissions testing of construction products. This is expected to form part of the CE marking process that will be backed by legislation across Europe. Considering the vast number and varied nature of the compounds likely to be present in the products included in any new or refurbished building, such control on chemical emissions may be regarded by many as being long overdue.
The first paper in the issue (Walsh, 2010) deals with European standards for road construction in the UK. The introduction of European standards for construction materials generally is a subject matter that will continue to arouse a good deal of debate in the industry. The process of delivering a standard is described and is shown to be complicated by national interests and the specific climatic conditions of the various European countries. The paper also highlights the benefits of having Europe-wide standards, such as the introduction of quiet and safe road surfacings into the UK.
The use of local materials to drive down cost and utilise available materials continues to be of interest and the paper by Pan and Razak (2010) is an example of such an approach. The authors discuss how kaolin can be calcined to make it suitable as a partial cement replacement additive for inclusion into concrete mix designs. The effect of calcined kaolin on the workability of the mix and physical properties of the hardened concrete such as compressive strength, surface absorption and water absorption are explained.
The paper by Lachemi et al. (2010) compares the methods used for the prediction of strength development and maturity of concrete taking account of retarder dosages. Being able to fine-tune any aspect related to fast methods of construction in the field of concrete technology is to be welcomed, particularly with the constant pressure on the industry to enhance construction times.
The experimental data produced by Poursaee and Hansson (2010) in the next paper essentially questions the belief that 7-day wet curing of high-performance concrete as locally specified in Ontario is necessary to ensure optimum durability. The results suggest that such curing might be unnecessary. Taking commonly-held beliefs to task is surely an effective method of understanding the mechanisms involved and also a way of questioning site processes and practices that might well be unnecessary.
The in-situ strengthening of concrete beams using techniques such as carbon fibre wrapping is a useful method that has been employed where inadequate strength from design errors, workmanship mistakes or where change of use has necessitated strength improvement. Other possible alternatives include the considerably more expensive demolition and reconstruction. The paper from Aldajah et al. (2010) describes a potential improvement to the structural analysis of the strengthening technique and could be especially helpful for designers to accurately predict deflections.
The final paper by Jayakumar and Saravanane (2010) describes the analytical techniques used to demonstrate how concrete can be affected by the biological activity of algal growth in seawater around the coast of India. The results show an unexpected yet challenging aspect of concrete durability.
I trust you will find the briefings and papers featured in this issue of interest and appreciate the efforts and hard work of the authors involved.
