Analytical Techniques for Detection of Oil Presence in Mortar

Oils, e.g. linseed oil, has been used as mortar admixtures or components of lime-oil mastic since ancient times. The reason was either to increase the mortar durability and/or to prolong the mortar/mastic workability. Historic mortars are conventionally analyzed by means of X-ray diffraction and thermal analysis, but these methods are not able to detect the organic compounds directly. The goal of the present research was to evaluate the applicability of thermal analysis, infra-red spectroscopy, solid state NMR spectroscopy and gas chromatography for detection and possible quantification of linseed oil in prepared mortar containing, beyond the oil, just lime and calcite. Both applied spectroscopies were able not only detect the presence of oil but may be used also for study of the oil chemical transformation in the alkaline environment of the lime mortar. Thermal analysis is not able to identify kind of organic admixture, but when it is known that it is e.g. linseed oil, its quantification by help of Evolved Gas Analysis is very good. The results of gas chromatography of mortar’s extract are affected by the polymerization of oil in mortar. The total organic content analysis is providing good information about the total amount of organics in mortar. There in not any single method, which could provide all information about the oil admixture in mortar (kind of oil, content of oil, fate of oil after mortar’s mixing) by itself; the combination of techniques must be used.

Experimental Determination of Early Shrinkage of Alkali-Activated Slag

This paper deals with the relationship between chemical processes in the early stages of hydration of alkali-activated slag, volume changes and the development of the microstructure of this material. Two test pastes were produced for the purpose of the experiment - one with and the other without an organic admixture (isopropyl alcohol). The pastes were used to monitor autogenous shrinkage by measuring volume changes and at the same time the changes in the material during setting and early hardening using a modern ultrasonic instrument Vikasonic. The output of the described experiment is a detailed evaluation of the difference in the behaviour of the used alkali-activated paste with and without the addition of an organic admixture.

Seedling emergence of Pinus sylvestris in characterized seedbed substrates under different moisture conditions

Establishment of Scots pine (Pinus sylvestris L.) stands from seed is often unsuccessful because of unsuitable environmental conditions, such as limited soil moisture or air humidity. Improved seedling emergence could be achieved by soil preparation if site-specific optimal seedbeds were specified. Therefore the effects of seedbed substrates (13 characterized mixtures of sand, silt, and organic matter) on seedling emergence were determined after 14-day emergence tests in small laboratory chambers with four moisture conditions (2 levels of relative air humidity (RH), 95 and 65%, in combination with 2 levels of substrate water tension, 3 and 10 kPa). Seeds were placed in (partially buried) and on noncompacted and compacted substrates. At 95% RH, seedling emergence was 80 to 95% (seed lot maximum 94%) regardless of the substrate, with the exception of seeds placed in silt substrates (30-70%). At 65% RH, seedling emergence was 90% on silt, but considerably lower on organic matter and sand substrates, where organic admixture improved emergence for sand, but had a neutral or negative effect for silt. At 65% RH, partial seed burial, i.e., with good seed-substrate contact, improved emergence for organic matter and sand substrates, but impaired emergence for pure silt in noncompacted substrates at 3 kPa soil water tension. The effect of compaction on emergence was small for most substrates and had an effect only at 65% RH and 10 kPa tension. Seedling emergence and soil hydraulic conductivity at 3 kPa water tension and 95% RH were negatively correlated for partially buried seeds, but regardless of seed position, they were positively correlated at 10 kPa tension and 65% RH. These results can be used as guiding principles for the creation of seedbed substrates and seeding techniques.