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Abstract: An estimated 1000 million tyres reach the end of their useful lives every year and 5000 millions more are expected to be discarded in a regular basis by the year 2030. Up to now a small part is recycled and millions of tyres are just stockpiled, landfilled or buried. This paper presents results about the properties and the durability of HPC with partial replacement of sand by tyre rubber wastes. Fly ash and metakaolin are used as partial cement replacement. The durability performance was assessed by means of capillary water absorption and resistance to sulphuric acid attack. The results show the existence of a synergetic effect between fly ash and metakaolin that minimizes the strength loss associated to the use of rubber waste. Results also show that is possible to use rubber waste up to 15% and still maintain a high resistance to acid attack. The mixes with 45% fly ash and 15% metakaolin show a much higher resistance to sulphuric acid attack than the reference mix independently of the rubber waste content. [Copyright &y& Elsevier]

Abstract: The volume of polymeric wastes like tyre rubber and polyethylene terephthalate bottles (PET) is increasing at a fast rate. An estimated 1000 million tyres reach the end of their useful lives every year and 5000 millions more are expected to be discarded in a regular basis by the year 2030. Up to now a small part is recycled and millions of tyres are just stockpiled, landfilled or buried. As for PET bottles annual consumption represent more than 300,000 million units. The majority is just landfilled. This paper reviews research published on the performance of concrete containing tyre rubber and PET wastes. Furthermore it discusses the effect of waste treatments, the size of waste particles and the waste replacement volume on the fresh and hardened properties of concrete. [Copyright &y& Elsevier]

Abstract: The ceramic industry is known to generate large amounts of calcined-clay wastes each year. So far a huge part is used in landfills. Reusing these wastes in concrete could be a win–win situation. For one hand by solving the ceramic industry waste problem and at the same time leading to a more sustainable concrete industry by reducing the use of non renewable resources like cement and aggregates and avoiding environmental problems related to land filled wastes. This paper examines the feasibility of using ceramic wastes in concrete. Results show that concrete with 20% cement replacement although it has a minor strength loss possess increase durability performance. Results also show that concrete mixtures with ceramic aggregates perform better than the control concrete mixtures concerning compressive strength, capillary water absorption, oxygen permeability and chloride diffusion thus leading to more durable concrete structures. [Copyright &y& Elsevier]

Abstract: Classic approaches to polymer-modificated Portland cement based materials usually forget the specific nature of the precast concrete industry and also the economic impacts of each technical option. This manuscript report results of a wider investigation which aims to understand what is the best option for the concrete pipe industry as far as sulphuric acid resistant is concerned, polymer addition or polymer impregnation. Results show that the use of polymer addition it is not economically attractive when compared to polymer impregnation. The increase of costs per meter of pipe is too high. The use of polymer impregnation enhances the chemical resistance of concrete considerably. Furthermore, it is economically viable, especially for smaller diameters. Results also show that using sulphate resistant cements improve the chemical resistance without cost increase. [Copyright &y& Elsevier]

Abstract: This paper presents an experimental study to evaluate the influence of physical and geometrical properties of granite and limestone aggregates on the durability of a C20/25 strength class concrete. Different granite and limestone aggregates were collected from seven quarries. Physical, geometrical and mechanical properties of aggregates as well as the rock weathering state were quantify by several tests such as, abrasion, surface hardness, uniaxial compressive strength, ultrasonic pulse velocity, water absorption by capillarity, vacuum water absorption and oxygen permeability. Using aggregates from each quarry, several C20/25 strength class concrete mixes have been produced, with the same workability and volume proportions. Concrete specimens have been cured under water for 90 days; after that time concrete durability parameters were obtained through tests such as, vacuum water absorption, capillarity water absorption, water permeability and oxygen permeability. Relevant statistical correlations have been obtained between absorption and permeability test of rock material and rock deterioration state (weathering). Valid statistic correlation was also obtained between durability parameters as well as among aggregates geometrical properties and concrete durability parameters. [Copyright &y& Elsevier]

Highlights: [•] Fibres are added for improving the weak bond capacity between GFRP rebar and concrete. [•] The various fibres show positive hybrid effect on the bond effect between GFRP and concrete. [•] The bond capacity of GFRP in concrete with fibres is better than that of steel rebar in concrete. [•] The hybrid use of different macro fibres provides also cost benefit. [Copyright &y& Elsevier]