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Nanotechnology seems to hold the key that allows construction and building materials to replicate the features of natural systems improved until perfection during millions of years. This paper reviews current knowledge about nanotechnology and nanomaterials used by the construction industry. It covers the nanoscale analysis of Portland cement hydration products, the use of nanoparticles to increase the strength and durability of cimentitious composites, the photocatalytic capacity of nanomaterials and also nanotoxicity risks.

The construction industry is responsible for the depletion of large amounts of nonrenewable resources. This activity generates not only millions of tons of mineral waste but also millions of tons of carbon dioxide gas emissions. Therefore, research about building materials based on renewable resources like vegetable fibres is needed. This paper discusses the use of vegetable fibres as reinforcement in cement based materials. It includes fibre characteristics, properties and the description of the treatments that improve their performance; it covers the compatibility between the fibres and the cement matrix and also how the fibres influence cement properties. It also includes the properties and durability performance of cementitious materials reinforced with vegetable fibres. Furthermore future research trends are also suggested.

This paper summarizes current knowledge about alkali-activated binders, by reviewing previously published work. As it is shown in Part 1, alkali-activated binders have emerged as an alternative to (ordinary Portland cement) OPC binders, which seem to have superior durability and environmental impact. The subjects of Part 2 of this paper are prime materials, alkaline activators, additives, curing type and constituents mixing order. Practical problems and theoretical questions are discussed. Topics for future work in this field are suggested.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright

No abstract

The disintegration of concrete structures made of ordinary Portland cement (OPC) is a worrying topic of increasing significance. The development of new binders with longer durability is therefore needed. Alkali-activated binders have emerged as an alternative to OPC binders, which seems to have superior durability and environmental impact. This paper reviews current knowledge about alkali-activated binders. The subjects of Part 1 in this paper are historical background, terminology and hydration products. The proper terminology to designate these new binders will be discussed. The influence of the prime materials and the type of alkaline activator on the reaction mechanisms and on the nature of the reaction products will be described.

This paper presents an experimental study on the properties and on the durability of concrete containing ceramic wastes. Several concrete mixes possessing a target mean compressive strength of 30 MPa were prepared with 20% cement replacement by ceramic powder (W/B = 0.6). A concrete mix with ceramic sand and granite aggregates were also prepared as well as a concrete mix with natural sand and coarse ceramic aggregates (W/B = 0.5). The mechanical and durability performance of ceramic waste based concrete are assessed by means of mechanical tests, water performance, permeability, chloride diffusion and also accelerated aging tests. Results show that concrete with partial cement replacement by ceramic powder although it has minor strength loss possess increase durability performance. Results also shows that concrete mixtures with ceramic aggregates perform better than the control concrete mixtures concerning compressive strength, capillarity water absorption, oxygen permeability and chloride diffusion. The replacement of cement and aggregates in concrete by ceramic wastes will have major environmental benefits.