An overview is given of all results from the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials), which was launched in 1985. Since then, about twenty different materials have been exposed repeatedly in a network of test sites consisting of more than twenty sites with an extensive environmental characterisation and more than sixty official reports have been issued. Recent results on trends in corrosion, soiling, and pollution show that corrosion of carbon steel, zinc, and limestone is today substantially lower than 25 years ago, but while corrosion of carbon steel has decreased until today, corrosion of zinc and limestone has remained more or less constant since the turn of the century. Unique data are given on measured HNO3concentrations from 2002-2003, 2005-2006, and 2008-2009, and the relative average decrease was about the same from 2002-2003 to 2005-2006 as it was from 2005-2006 to 2008-2009.

This article presents the results of microstructural investigation of high strength concrete containing microsilica and nanosilica (amorphous SiO2) as an active pozzolanic admixture. Micro and nanosilica react with calcium hydroxide producing calcium silicate hydrates (C-S-H), thus the voids and pores within concrete are filled and new minerals are formed in the gaps between cement grains and aggregate particles. Unreacted round microsilica and nanosilica particles were registered using SEM even in 6 month old samples. The compressive strength results indicate that concrete still continues to harden after the 28-days of curing.

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The sewage sludge from a water purification plant was analysed for recycling to the dense glass-ceramic materials. The sewage sludge containing aluminium compounds and circa 50 % of organic matter was used as a filler, but as the matrix of glass-ceramic was examined an illitic clay from Liepa deposit (Latvia). The raw materials were investigated by differential-thermal (DTA) and X-ray diffraction analysis (XRD). The dense glass-ceramic was produced from the water purification sewage sludge and limeless clay in ratio 10-40 : 90-60. The optimal values of bulk density (2.28 g/cm 3 ) and thermal shrinkage (29 %) for novel materials were observed for glass-ceramic with the sludge additive at amount of 20 wt %, obtained by sintering at temperature 1140 °C. The relationship between thermal treatment conditions and maximal treatment temperature was established. The following crystalline phases for novel materials were detected by XRD analysis: microcline (KAlSi 3 O 8 ), hematite (Fe 2 O 3 ), quartz (SiO 2 ) and corundum (Al 2 O 3 ). The physical-chemical properties of novel materials correspond to the dense glass-ceramics composite while the material itself could be applied as building material.

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