Concrete construction methods and practices influence the final in-place quality of concrete. A low permeability concrete mixture does not alone ensure quality in-place concrete. If the concrete mixture is not transported, placed and cured properly, it may not exhibit the desired durability and mechanical properties. This study investigates the in-place permeation properties of low permeability concrete bridge decks mixtures used in the Commonwealth of Virginia. Permeation properties were assessed in both the laboratory and in the field using 4-point Wenner array electrical resistivity, surface air flow (SAF), and chloride ion penetrability (ASTM C 1202-97). Laboratory test specimens consisted of two concrete slabs having dimensions of 280 x 280 x 102-mm (11 x 11 x 4-in) and twelve 102 x 204-mm (4 x 8-in) cylinders per concrete mixture. Specimens were tested at 7, 28 and 91-days. Thirteen cylinder specimens per concrete mixture underwent standard curing in a saturated limewater bath. The simulated field-curing regimes used wet burlap and plastic sheeting for 3 (3B) and 7 days (7B) respectively and was applied to both slabs and cylinder specimens. Slab specimen were tested on finished surface using the SAF at 28 and 91 days, and 4-point electrical resistivity measurements at 1, 3, 7, 14, 28 and 91 days. Compressive strength (CS) tests were conducted at 7 and 28 days. Chloride ion penetrability tests were performed at 7, 28, and 91 days. Statistical analyses were performed to assess the significance of the relationships for the following: Total charge passed and initial current (ASTM C 1202-97); 3B resistivity and 7B resistivity; Slab and cylinder resistivity; Slab resistivity and ASTM C-1202-97 (Total Charge and Initial current); and Surface Air Flow and ASTM C-1202-97. Field cast specimens, test slabs and cylinders, were cast on-site during concrete bridge deck construction. The slab dimensions were 30.5 x 40.6 x 10.2-cm (12 x 16 x 4 in.), and the cylinders were 10.2 x 20.4-cm (4 x 8-in). In-situ SAF and resistivity measurements were taken on the bridge deck at 14, 42 and 91 days. In-place SAF and resistivity measurements on laboratory field cast slabs were taken at 7, 14 and 28-days. ASTM C 1202-97 specimens were prepared from field cast cylinders and tested at 7 and 28 and 42-days. The relationship between in-place permeation measures from field specimens was compared to laboratory data. Results indicated no difference in chloride ion penetrability (Figures 7.4 and 7.5) and 28-day compressive strength (Figure 7.2) with regard to differing simulated field curing regimes, for same age testing. There was no significant difference at the 95 % confidence level between 3B resistivity and 7B resistivity specimens tested at the same age (Figures 7.9 and 7.10). A well defined relationship was observed between total charge passed and initial current (Figure 7-6). An inverse power function was found to describe the relationship between charge passed/initial current and electrical resistivity for all laboratory mixtures used in this study (Figure 7.17 – 7.22). Field data was used to validate laboratory established models for charge passed/initial current and electrical resistivity. Laboratory established models were able to predict 30 to 50% of the field data (Figures 7.31 – 7.34). Results indicate that the SAF lacked the sensitivity to classify the range of concretes used in this study (Figure 7.24). / Ph. D.

Im Rahmen holztechnologischer Prozesse wie dem Holzschutz, der Holzmodifizierung oder der Zellstoffherstellung sind die Eindringwege von Flüssigkeiten in das Holz von großem Interesse. Neben den Eigenschaften des Tränkmittels und der Gestaltung des Tränkprozesses stellt der Aufbau des Holzes einen der wesentlichen Einflussfaktoren hinsichtlich der Permeabilität des Holzes für Flüssigkeiten dar. Der Artikel gibt einen Überblick über den Einfluss mikrostruktureller Eigenschaften des Holzes auf dessen Tränkbarkeit.

Cement penetrability is a key factor in multifilament cement composites. However, the modes of action and the concepts vary because of brittle and ductile fibers. In the case of brittle fibers such as glass, high penetrability of cement products in between the bundle filaments can lead to brittle composite behavior, and therefore addition in ductility is required. In order to have efficient bundle action and high bonding, fillers can be introduced in between the glass filaments, keeping the telescopic mode of failure but at the same time improving the bond and stress transfer within the filaments of the bundle, even at late ages, resulting in a ductile and high strength composite. On the other hand, ductile fibers such as polypropylene (PP), which also developing low bonding with the cement matrix, result in ductile cement composite but with relatively low strength. Therefore, in this case good penetrability of the cement in between the filaments of the bundle is essential in order to maximize the reinforcing efficiency of the bundle by improving bond. The penetrability of the matrix into a fabric structure and especially in between the bundle filaments made up the fabric is a result of fiber- matrix compatibility, which depends on: level of opening and spaces between the filaments, bundle surface properties including wetting and chemical affinity to the cement matrix, matrix viscosity, processing of the composite, and the nature of the fabric junctions and the resulting tightening effects of the bundle, i.e., influenced by the fabric structure itself.

Mental images are unique mental representations and the depictive view in the imagery debate states that mental images have similar spatial structures as their corresponding external object. The propositional view, however, contends that beliefs about the external world influence a mental image – also known as the cognitive penetrability theory –, therefore mental images cannot be described in visual terms. People with self-described aphantasia, those considered lacking visual mental images, offer a new opportunity to approach this issue. The current study employed the mental rotation task (MRT), where a three-dimensional object needs to be mentally aligned with another one that is rotated to a different angular position. To test the effects of beliefs on mental images, different instruction conditions were used on the MRT. Twenty-seven participants (21 females, mean age 47 years) with self-described aphantasia completed an online experiment, consisting of the MRT, the Object-Spatial Imagery Questionnaire (OSIQ), and the Vividness of Visual Imagery Questionnaire (VVIQ). While participants scored low on the VVIQ and higher on the spatial items than on the object items of the OSIQ, the key finding was that increasing reaction time with increasing angular disparity on the MRT was not influenced by different instruction types. This suggests that the theory of cognitive penetrability is not applicable on mental rotation in aphantasia, highlighting the importance to revise how mental images (or the lack of them) are understood and described.

In the past centuries, grouting has been one of the most common techniques in geotechnical engineering to strengthen and seal underground structures. Concerning increasing demands for tightness and cost efficiency, cement-based grout has been one the most frequent used materials. One of the first grouting operations is the work done by Charles Bérigny in France back in 1802 in order to repair a sluice by stabilizing the ground with liquid grout. Several studies have been then conducted in grouting, which have contributed into successful improvement of the grouting operations. The investigations have also extended the understanding of the factors such as choice of materials, choice of equipment, and the applied pressure type and magnitude, etc. that influencing the grout spread in rock fracture systems.   Among the factors, the applied pressure is one of the most significant ones influencing the spread of grout during grouting operations. Grouting at static pressure conditions is the most common method used in field, where in practice the injected grout can only penetrate into the rock fractures wider than 100 µm.   Recent investigations conducted on application of static and dynamic pressure conditions, using Short Slot and Varying Aperture Long Slot (VALS) in the lab have yielded an overall improvement of the grout spread under dynamic pressure conditions rather than the conventional static pressure conditions. However, the efforts conducted are just a beginning, especially in very fine micro factures smaller than 70 µm    The main objective of this investigation was therefore to improve the spread of grout by dynamic grouting into fractures smaller than 70 µm effectively, which could not be done with grouting at static pressure conditions.  Furthermore, the aim was to investigate filtration and erosion phenomena/ tendency of grout flow during static and dynamic pressure application using Varying Aperture Long Slot (VALS) in the lab. The durations of peak and rest periods used in the experiments were 2s/2s and 1s/5.5s, which were equivalent to 0.25 Hz and 0.15 Hz, respectively. The results of dynamic grouting showed up to 10 times improvement in the volume of passed grout through fracture apertures smaller than 70 µm. / Injektering är en av de vanligaste metoderna som använts för att förstärka och täta geotekniska konstruktioner. När det gäller ökande krav på täthet och kostnadseffektivitet har cementbaserade bruk varit ett populärt förbrukningsmaterial. Injektering användes förmodligen först av Charles Bérigny i en slussreparation i Frankrike under 1802 där marken stabiliserades med hjälp av flytande injekteringsmaterial. Flera studier har sedan dess utförts inom injekteringsteknik, vilket har bidragit till en framgångsrik förbättring av injekteringsoperationer. Dessa undersökningar har också utvidgat förståelsen av faktorer såsom materialegenskaper, val av utrustning, provprestanda, trycktyp och storhet som i sin tur påverkar brukets spridningsförmåga i bergets spricksystem.   Forskningen inom bergtätning fokuserar bland annat på att utveckla tillämpningen av statisk och dynamisk tryck vid injektering. Tillämpning av statiskt tryck är den vanligaste metoden för injektering ute i arbetsfält, där den injicerade bruket i praktiken endast kan tränga in i bergssprickor som är större än 100 μm.   De senaste undersökningarna med hjälp av Short Slot och Varying Aperture Long Slot (VALS) har visat en övergripande förbättring av inträngningen under dynamisk injektering jämfört med de konventionella statiska. Detta är bara en början och metoden behöver utvecklas mer, särskild för att åstadkomma bruksspridningen i mycket finare mikrosprickor, exempelvis sprickor mindre än 70 µm.   Syftet med detta arbete var att utveckla injekteringsmetoden där bruket kan tränga  i berg med sprickor mindre än 70 µm. Resultaten på de dynamiska tryckförhållanden visade att injekteringsbruket trängde bättre  i de smala sprickor  jämfört med de statiska tryckförhållanden. Upp till 10 gånger mer mängd av injekteringsbruk passerade sprickor med storlek mindre än 70 µm i VALS. Vidare har inloppsflödet och filtrerings- och erosionsfenomenen studerats med hjälp av laboratorieinstrumentet VALS. Varaktigheten av peak- och restperioder som användes i experimenten var 2s/2s och 1s 5.5s, vilka var ekvivalenta med 0.25 Hz respektive 0.15 Hz.

This paper contains a basic overview and description of optical lenses. It introduces different types of optical lenses and shows how they influence the passing of light beams. It deals with the production of optical lenses and their practical use. It describes types of optical blemishes that exist in real optical systems. Particular attention is given to parameters of optical lenses and their measurement in practice. It includes a Matlab program to calculate parameters of optical lenses derived from the measurements.