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Basalt Fibre Reinforced Polymer (BFRP) is a new material in civil engineering and has shown to be a promising material for infrastructure strengthening. In comparison to carbon fiber, glass fiber and other composites, it has some advantages such as high-temperature resistance and low cost. At the Structural and Composite Laboratory at Reykjavik University (SEL) several research projects involving strengthening concrete beams and columns by using FRP materials have been on-going in recent years. These tests have shown improvements in strength and durability compared to unstrengthened concrete members. The benefit of using basalt fiber or other FRP material is that they are non-corrosive, which is a good choice for reinforcing concrete structure exposed to de-icing salts, for examples in bridge decks and parking garage elements. Also for concrete exposed to marine environment, such as seawalls, water breaks and buildings or other structures located near a waterfront. Two research projects are presented in this paper; a test of prestressed concrete with internal basalt rods instead of steel and a test of columns strengthened by wrapping fibre-reinforced composite sheets around the columns to increase their strength and ductility. These experimental tests show increasing strength and ductile for both the beams and the columns.

Efflorescence is one of the limitations of the widespread use of geopolymers. This problem is caused by excess unreacted sodium oxide remaining inside materials. Unreacted sodium oxide creates white efflorescence on the surface of the produced material in the form of sodium carbonate heptahydrate Na2CO3∙ 7H2O. It decreases not only the aesthetic value of the final products, but also the mechanical properties of the material. The aim of this article is to analyse the influence of the curing method on the appearance of efflorescence on geopolymer composites reinforced by short basalt, especially on mechanical properties. Class F fly ash from the ‘Skawina’ coal-fired power plant (located in Skawina, Lesser Poland, Poland) was used as raw material for the geopolymerization process. The article compares two methods of curing: typical laboratory conditions (in the air) and samples submerged in water. Three series of fly ash-based geopolymer were cast: basalt fibres were added as 1% and 2% by weight of fly ash and one control series without any fibres. The investigation was performed using visual analysis, including microstructure investigation, and the testing of mechanical properties (compressive strength at ambient temperature) after 28 days.

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