Limestone Concrete Research Articles

A systematic account of the ammonite faunas of the Obtusum Zone (Sinemurian Stage, Lower Jurassic) from Marston Magna, Somerset, UK

The village of Marston Magna in Somerset, southwest England has long been celebrated as the source of the decorative ‘Marston Magna Ammonite Marble’, a name given to lenticular limestone concretions crowded with small ammonites of genera such as Promicroceras Spath and Asteroceras Hyatt. Most known specimens were collected during the 18th and 19th centuries and, based on museum specimens, their biostratigraphical provenance has been correlated with the Asteroceras blakei biohorizon, within the Stellare Subzone of the Obtusum Zone.Recent excavations at Marston Magna have exposed sections spanning ∼4m of argillaceous sediment of the Obtusum Zone. Concretionary nodules crowded with ammonites were found to occur at different horizons. Large ammonite and nautiloid body-chamber fragments, often containing small ammonites, were also recorded in situ. The sections encompassed faunas characteristic of the Asteroceras blakei and Aegasteroceras sagittarium biohorizons of Page, but the range of Asteroceras species close to Asteroceras blakei appeared to overlap with Aegasteroceras. This observation raises a practical difficulty in recognizing these two biohorizons, and the original discoveries of the Marston Marble are deduced to be from a horizon that is biostratigraphically higher than previously suspected. A new subgenus and two new species of eoderoceratid ammonite, Promicroceras (Leptomicroceras) cowapi subgen. et sp. nov, and Microderoceras nautilum sp. nov. are described and some systematic issues concerning well known ammonites are discussed in detail. The new family Asteroceratidae is proposed.

Assessment of Mass Fraction and Melting Temperature for the Application of Limestone Concrete and Siliceous Concrete to Nuclear Reactor Basemat Considering Molten Core–Concrete Interaction

Severe accident scenarios in nuclear reactors, such as nuclear meltdown, reveal that an extremely hot molten core may fall into the nuclear reactor cavity and seriously affect the safety of the nuclear containment vessel due to the chain reaction caused by the reaction between the molten core and concrete. This paper reports on research focused on the type and amount of vapor produced during the reaction between a hightemperature molten core and concrete, as well as on the erosion rate of concrete and the heat transfer characteristics at its vicinity. This study identifies themass fraction and melting temperature as the most influential properties of concrete necessary for a safety analysis conducted in relation to the thermal interaction between the molten core and the basemat concrete. The types of concrete that are actually used in nuclear reactor cavities were investigated. The H₂O content in concrete required for the computation of the relative amount of gases generated by the chemical reaction of the vapor, the quantity of CO2 necessary for computing the cooling speed of the molten core, and the melting temperature of concrete are evaluated experimentally for the molten core econcrete interaction analysis.

Paradoxidid trilobites from a mid-Cambrian (Series 3, stage 5) limestone concretion from Jämtland, central Sweden

This paper describes the morphology and discusses the taxonomy of the paradoxidid trilobites present in the moult ensemble described by Ebbestad et al. (2013) from a huge limestone concretion of the Alum Shale Formation collected at Ostnar, Jamtland. Two species, both represented by numerous but small complete holaspid specimens are described as new: Eccaparadoxides? thorslundi sp. nov. is distinctive, but its generic position is considered doubtful; Hydrocephalus spinulosus is similar to H. vikensis Rushton & Weidner, 2007 (also present as a rarity in the moult ensemble) and is partly distinguished from it by characters of the thorax. Also illustrated are a few specimens that have been collected at various localities between Hackas and Brunflo. They appear to represent individuals of some of the species in the moult ensemble and are about twice the size of their type specimens.

Nanostructured TiO2 for stone coating: assessing compatibility with basic stone’s properties and photocatalytic effectiveness

Many building materials have been functionalized to achieve photocatalytic properties, namely self-cleaning and depolluting abilities, through the application of photocatalytic TiO2 nanoparticles to those materials. These nanoparticles are able to preserve building facades by blocking the deposition of airborne particulates in polluted urban environments, and they are able to purify the air, thus benefiting the environment. In this study, the application of nanostructured TiO2 as a photoactive coating on two types of natural stone was investigated. A TiO2 sol obtained by sol–gel synthesis followed by hydrothermal processing was applied via spray deposition onto a compact limestone and a highly porous calcarenite. The effects of this coating on some basic properties of the stone, such as its color and water absorption, and the photocatalytic effectiveness of the coated surface were then studied. Scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that the coating presented a uniform morphology on both types of stone, with the TiO2 nanoparticles penetrating <1 µm into the stone. The coating was found to be compatible with the properties of the investigated types of stone. Colorimetry indicated that the change in the color of the stone due to the coating was negligible. Measurements of the static contact angle and the results of the capillary water absorption test showed that photoinduced superhydrophilicity did not increase the amount of the water absorbed by the coated stone. A photodegradation test of rhodamine B demonstrated the self-cleaning ability of the coating on both types of stone. Conversely, the photocatalytic effectiveness of the coating—as measured by a nitrogen oxide abatement test—was found to be higher for the porous calcarenite than for the compact limestone, and to depend on the porosity and roughness of the substrate.

A new phosphatic‐shelled cirripede (Crustacea, Thoracica) from the Lower Jurassic (Toarcian) of Germany – the oldest epiplanktonic barnacle

AbstractA new genus and species of phosphatic‐shelled eolepadid barnacle from the Posidonia Shale (Toarcian, falciferum Zone) of Zell u. Aichelberg, southern Germany, is described as Toarcolepas mutans gen. et sp. nov. Numerous disarticulated individuals, associated with fossil wood, are present in a piece of concretionary limestone, and these are interpreted as having lived epiplanktonically attached to driftwood. The taxonomy of the Late Triassic – Early Cretaceous family Eolepadidae is reviewed, and two further species (T. gaveyi (Withers, 1920) and T. lotharingica (Méchin, 1901)) are referred to Toarcolepas. The chemistry of valve composition of the Carboniferous Praelepas and Triassic–Jurassic eolepadid cirripedes is investigated using X‐ray dispersive analysis, and the ubiquitous presence of abundant phosphorus is taken as evidence that these taxa had a primary phosphatic composition, now preserved as francolite. A significant change in shell chemistry from phosphate to calcium carbonate took place during the evolution of the Thoracica, during the Late Triassic or Early Jurassic. The driving force behind this change may have been related to the reduced predation pressure associated with acquisition of an epiplanktonic mode of life. Calcite is softer, but energetically cheaper to deposit than phosphate mineral phases.

Utilisation of crushed floor and wall tile wastes as aggregate in concrete production

Industrial wastes are often used as aggregate in concrete production to lower their production cost. Large quantities of tiles are discarded during the tile production in the ceramic factories due to substandard and low quality production. The tile waste can reach up to 7% of the total tile production in the ceramic tile sector. At present, the tile wastes are not used for any purposes in Turkey, they are continuously stored at waste dumps.Studies are carried out to determine the possibility of using the tile waste as aggregates in concrete production to decrease the production cost and also to minimise the environmental impact of tile wastes. Properties of tile made concretes are compared with the properties of the concrete made using the limestone aggregates. The concrete made using the crushed floor tile aggregates have been found to have similar mechanical properties with that of the limestone concrete, on the other hand the concretes made with the wall tile aggregates have given lower mechanical properties than the limestone concrete.

Effect of Limestone Composition and Microstructure on the Strength of Aggregates and Concretes

Limestone rock aggregates were collected from the Fayoum depression southwest of Cairo, Egypt. The chemical and mineral composition as well as the microstructure of the aggregates was studied using XRF, XRD and transmitted light microscopy, respectively. Other tests were carried out on the aggregates including uniaxial compressive strength, bulk density, porosity and water absorption. It can be concluded that sample A is entirely limestone and sample C is dolomitic limestone, while sample B shows the presence of quartz as an essential mineral beside calcite and minor dolomite. The compressive strength confirms that sample C has the highest value so it was selected to form concrete as it recorded the best results. Uniaxial compressive strength, bulk density, porosity and water absorption as well as microstructure of the concrete were investigated using SEM. The compressive strength of the dolomitic limestone concrete (520.86 kg/cm2) is much higher than the aggregate itself (424.02 kg/cm2) due to the bonding strength of the aggregate cement interface. It was concluded that the engineering behaviour of aggregates plays an important role in concrete strength. Use of the dolomitic limestone aggregates in concrete in substitution of coarse aggregates for construction was recommended.

The interactions of molten core with different types of concretes in EPR severe accident

Sacrificial concrete is very important in the advanced European pressurized water reactor (EPR). To compare the behaviors of different kinds of sacrificial concretes in the EPR reactor pit, several sacrificial concretes were adopted in the calculation of molten core–concrete interaction molten core-concrete interaction (MCCI), i.e. the “FeSi” concrete, the siliceous concrete, and the limestone concrete. Using a computer code MELCOR, the main parameters, i.e. concrete ablation depth and rate, hydrogen generation mass and rate and temperature in a typical small break loss of coolant severe accident in EPR were calculated. The results indicate that the ablation rate decreased in the order of the “FeSi” concrete, siliceous concrete and limestone concrete. Meanwhile, the generated hydrogen mass of the “FeSi” concrete is 13% less than that of the siliceous concrete. In addition, as the basemat of reactor pit is melt through, the temperature of melt pool is the lowest for the limestone concrete and the temperature of siliceous concrete is slightly higher than that of “FeSi” concrete.

Multi-scale investigation of the performance of limestone in concrete

Limestone (calcium carbonate, CaCO3) has long been a critical component of concrete, whether as the primary raw material for cement production, a fine powder added to the binder component, or a source of fine and/or coarse aggregate. This paper focuses on the latter two of these examples, providing a multi-scale investigation of the influences of both fine limestone powder and conventional limestone aggregates on concrete performance. Fine limestone powder in the form of calcite provides a favorable surface for the nucleation and growth of calcium silicate hydrate gel at early ages, accelerating and amplifying silicate hydration, and a source of carbonate ions to participate in reactions with the aluminate phases present in the cement (and fly ash). Conversely, the aragonite polymorph of CaCO3 exhibits a different crystal (and surface) structure and therefore neither accelerates nor amplifies silicate hydration at a similar particle size/surface area. However, because these two forms of CaCO3 have similar solubilities in water, the aragonite does contribute to an enhancement in the reactivity of the aluminate phases in the investigated systems, chiefly via carboaluminate formation. In 100% ordinary Portland cement (OPC) concretes, 10% of the OPC by volume can be replaced with an equivalent volume of limestone powder, while maintaining acceptable performance. A comparison between limestone and siliceous aggregates indicates that the former often provide higher measured compressive strengths at equivalent levels of hydration, even when the two aggregate types exhibit similar elastic moduli. This suggests that the interfacial transition zone in the limestone-based concretes exhibits a higher degree of bonding, likely due to the favorable physical (texture) and chemical nature of the limestone surfaces. These observations reinforce the value of utilizing limestone to increase the performance and sustainability of 21st century concrete construction.

Travertine: Distinctive depositional fabrics of carbonates from thermal spring systems

AbstractThe terrestrial limestones forming at the emergence of thermal springs show a variety of unusual depositional facies. The specific lithological and petrological features of these deposits have few counterparts in the marine, and continental, karst‐related carbonates, but they are typical of the epigean limestone that has been quarried since antiquity in the surroundings of Tivoli (Rome) under the name of travertine, where it is still forming in hydro‐geothermal fields linked to extensional tectonics. The physicochemical, hydrodynamic and geological conditions specific to the Tivoli thermal spring system imply hypersaturated alkaline–sulphate, warm to hot waters, upwelling from springs fed through open fractures/faults in extensional and/or volcanic regimes. These features, together with the hydrodynamic behaviour of the water flows running from the vents, control the petrogenetic features of the travertine, a well‐bedded, mostly finely laminated, porous but quite compact limestone. The results of a detailed comparative petrological analysis carried out on the lithofacies of travertine limestones, and of those observed during formation within numerous active thermal spring fields, provide the elements required for an exhaustive textural classification of the travertine lithofacies, which has not yet been described systematically. According to the genetic processes and fabrics, the thermal deposits that originate from such hypersaturated alkaline–sulphate, warm to hot waters, can be subdivided into: abiotic crystalline crusts, microbially mediated crusts (microbialites) and granular deposits mostly represented by small accumulations of lime‐mudstone. Some of the granular deposits and the microbialites are only partially comparable with analogous sediments forming on tidal flats/sabkhas or other continental sites; however, the facies association of crystalline crusts and laminar curled microbialites has no counterpart in the marine realm. The widespread presence of thermophile bacteria and sulphobacteria, and the general absence of autochthonous eukaryote organisms, unable to live in poisonous sulphate waters, are also undeniable evidence of their thermal origin.

The Skull Structure of theMosasaurus,Explained by Means of a Description of a New Species of this Genus;

EDITOR'S NOTES: The following is a translation of: Goldfuss, A. 1845. Der Schädelbau des Mosasaurus, durch Beschreibung einer neuen Art dieser Gattung erläutert. Nova Acta Academa Ceasar Leopoldino-Carolinae Germanicae Natura Curiosorum 21: 1–28. The paper represents the first detailed description of a mosasaur skull. Although prepared and described in Germany, the remains came from the Late Cretaceous rocks along the Missouri River in South Dakota. The missing anterior portion (snout) of the skull and other fragments had been collected earlier by a trapper and mistakenly described by Dr. Richard Harlan (1834) as part of the skull of Ichthyosaurus missouriensis. The remains subsequently disappeared and were thought to be lost, but the snout was recently relocated in the National Museum of Natural History in Paris by Caldwell and Bell (2005). Prince Maximilian zu Wied acquired the rest of the specimen during his travels in North America in 1832–1834 and shipped it back to Germany. There Dr. Georg August Goldfuss (1782–1848; Fig. 1) spent nearly eight years meticulously removing the bones from the surrounding limestone concretion. At the time of publication, other scientists were certain that the Harlan specimen was actually part of the Goldfuss Mosasaurus (see Von Meyer, 1845).His description and actual sized, highly detailed plates include many of the features later claimed as discoveries by Cope and Marsh, including “the parietal and jugal arches, the pterygoids and vomers, the position of the quadrate and the presence of sclerotic plates” around the eye (Williston 1898. p. 85; see also Russell 1967, Everhart 2005). Unfortunately, although Harlan had been terribly wrong about his identification of the original fragments of the specimen, his species name (missouriensis) has priority over Goldfuss' choice of Maximiliana, in honoring his benefactor.The paper was translated from the original German by Dr. Robert T. Firestone (ret.), University of Colorado, Boulder, Colorado Department of Germanic and Slavic Languages with assistance of the editor and Earl Manning, then at Tulane University. Most recently the context of the translation was improved by Sven Sachs (Engelskirchen, Germany).

The Test of Limestone Concrete Renewable Micromicropowder in Cement Production

This article through the test of impacts on mortar strength when limestone concrete recyclable micropowder replacing the cement in low volume, and analyze the phase of fired cement, then discussed the use of renewable cement. The test results showed that, with the new ground renewable micropowder replacing mortar cement, mortar strength did not decrease, but also increased, at the same time, renewable micropowder contains large numbers of CaCO3, which can be used as the raw materials of cement baking calcareous. However, the phase analysis of burning cement clinker XRD showed that the main mineral component of silicate cement clinker, which offering the feasibility strong support on cement production for the renewable micropowder.

Influence of Aggregates on Cracking Sensitivity of Concrete

Upon large demands from southwest of China where a large number of hydropower stations are schemed or under construction with presence of a variety of aggregates, it is of necessity to launch a comprehensive investigation on influence of aggregates on properties of concrete which was rarely reported before. Four types of aggregates selected from different construction sites were used to conduct tests, and results indicated that water absorption of aggregates exhibited a consistent rising tendency over 180 days and it had close relationship with autogenously shrinkage of concrete which varied in the manner that high water absorption of aggregates produced more obvious shrinkage. With employment of advanced temperature and stress machine, concrete made with diorite and basalt was rated better than limestone and natural granite concrete in crack resistance based on comparison of cracking temperature and thermal impact according to RILEM TC119.

Hydrodynamic behavior of Kangan gas-capped deep confined aquifer in Iran

The Kangan aquifer (KA) is located beneath the Kangan gas reservoir (KGR), 2,885 m below the ground surface. The gas reservoir formations are classified into nine non-gas reservoir units and eight gas reservoir units based on the porosity, water and gas saturation, lithology, and gas production potential using the logs of 36 production wells. The gas reservoir units are composed of limestone and dolomite, whereas the non-gas reservoir units consist of compacted limestone and dolomite, gypsum and shale. The lithology of KA is the same as KGR with a total dissolved solid of 333,000 mg/l. The source of aquifer water is evaporated seawater. The static pressure on the Gas–Water Contact (GWC) was 244 atm before gas production, but it has continuously decreased during 15 years of gas production, resulting in a 50 m uprising of the GWC and the expansion of KA water and intergranular water inside the gas reservoir. The general flow direction of the KA is toward the northern coast of the Persian Gulf due to the migration of water to the overlying formations via a trust fault. The KA is a gas-capped deep confined aquifer (GCDCA) with special characteristics differing from a shallow confined aquifer. The main characteristics of a GCDCA are unsaturated intergranular water below the confining layers, no direct contact of the water table (GWC) with the confining layers, no vertical flow via the cap rock, permanent uprising of the GWC during gas production, and permanent descend of GWC during water exploitation.

Early Palaeozoic carbonate reservoirs from the Yingshan Formation of Well block ZG-43 in Tazhong Low Rise, Central Uplift, Tarim Basin, NW China: geological features and controlling factors

Marine carbonate reservoirs, as a focus of petroleum exploration and development in China, are involved with high exploration risk and prediction difficulty owing to high heterogeneity and diversity of reservoir beds. In the Tarim Basin, NW China, carbonate reservoirs host about 38% of the whole basin's hydrocarbon resources in a large prospecting area mainly distributed in the Cambrian and Ordovician rocks in central (Tazhong) and northern (Tabei) Tarim. Recently, a better understanding has been made of the karsted weathering crust at the top of the Lower Ordovician Yingshan Formation in the northern slope area of the Tazhong Low Rise, Central Uplift, Tarim Basin. As a new frontier of exploration, oil/gas distribution and controlling factors of carbonate reservoirs in the Yingshan Formation are not clearly understood. In this work, we investigated the reservoir beds and oil/gas properties in 13 wells in Well block ZG-43 on the No. 10 structural belt in the Tazhong Low Rise, and studied hydrocarbon accumulation characteristics with seismic and geochemical data. The Yingshan Formation in Well block ZG-43 is mainly composed of calcarenite, dolomitic limestone, dolomite, cryptite, as low porosity and low permeability reservoir beds, with fracture-void porosity constituting the main reservoir pore space. Oil/gas is quasi-layer distributed beneath the unconformity between the Yingshan and Lianglitag formations to a depth of 140 m. The oil in Well block ZG-43 is condensate with low density, low viscosity, low sulphur, low resin, low asphaltene, and high wax. The gas is 87.3% methane, generally containing H2S. The oil/gas distribution pattern is oil in the east and gas in the west, and H2S content in the west is lower than that in the east. The controlling factors for hydrocarbon are multi-source supply and multi-phase charging, interstratal karstification, hydrothermal activity, structural location and sealing condition. A structural–lithological trap is the main type of oil/gas accumulation. Oil/gas distribution was clearly affected by strike–slip faults. Oil/gas with multi-source supply and multi-phase charging was controlled by favourable local palaeo-highs, and affected by later karsting and hydrothermal activity, as well as gas invasion in the Himalayan (Cenozoic) period. Under the caprock of compact limestone in the third to fifth members of the Lianglitag Formation, oil/gas migrated up along the strike–slip fault planes, and moved laterally to both sides in a ‘T’ shape, and formed large-scale quasi-layer condensate gas reservoirs controlled by reservoir bed quality. Copyright © 2013 John Wiley & Sons, Ltd.

CONCRETIONS AS SOURCES OF EXCEPTIONAL PRESERVATION, AND DECAY AS A SOURCE OF CONCRETIONS: EXAMPLES FROM THE MIDDLE DEVONIAN OF NEW YORK

Carbonate concretions (N = 18) from the Middle Devonian Hamilton Group were studied using CT X-ray imaging and with computerized 3-D reconstructions. Pyritized burrows and/or body fossils appear causally related to these concretions. When pyritization was noted on the outside of the specimen (N = 15), corresponding networks of pyritized full relief burrow traces could be demonstrated internally. Even when not noted externally, some evidence of pyritic, full relief burrows was noted in all specimens. Because of pyrite opacity, and density contrasts between the limestone concretions and pyrite, these burrows can be tracked through serpentine pathways using 3-D techniques. A brachiopod at the nucleus of one concretion displays X-ray evidence of a possible three-dimensional pedicle preserved in pyrite. This would then be one of the few known pedicles preserved in an articulate brachiopod in the fossil record. Halo formation around the shell edge suggests decaying visceral organic tissue as a probable source of a microbial biofilm, which, in turn, could have served as the nucleus of the concretion. A sequential mechanism is proposed in which both the mucous of burrowing organisms and the decay of visceral tissue served to localize pyritic crusts and concretions near the site of decay, followed by carbonate concretionary growth as pH increased, and available sulfide and iron decreased further from the decay source. These processes comprise end-members in a diagenetic continuum, based on a gradually changing local microbial and chemical environment. Increased bioturbation in studied concretions compared with surrounding sediment suggests increased residence time within the sulfate reduction zone due to sediment starvation following initial rapid burial. This diagenetic observation is suggested to apply to many other cases of concretion formation.

Diagenetic Implications of Stylolitization In Pelagic Carbonates, Canterbury Basin, Offshore New Zealand

Abstract Stylolites are irregular discontinuity surfaces that are thought to result from localized stress-induced dissolution during burial or tectonic compression. The genesis of stylolites and the controls on stylolitization are still debated, and the interplay between stylolitization, generation of carbonate-rich fluids, diagenetic fluid flow within fractures and matrix, cementation, and porosity modifications is complex. All of these processes have important diagenetic effects potentially altering the intrinsic properties of the host rock, with implications for hydrocarbon exploration and water resources in aquifers. We investigate the process of stylolitization by a macroscopic, petrographic, and geochemical study of pressure-solution features in Eocene to early Oligocene limestones in cores from the Integrated Ocean Drilling Program (IODP) Hole 317-U1352C (Canterbury Basin). The results indicate correlations among stylolite amplitude, stylolite density, and siliciclastic content of the host rock. These relationships are interpreted to suggest that siliciclastic content in carbonate rocks increases heterogeneity, which in turn impacts stylolite nucleation. Moreover, the geochemical data support that clay along the stylolite is not authigenic, but a relict from impurities in the limestone host rock. The statistical approach of stylolite spacing used in this study, which is different than previous studies, reinforces the model of random occurrence of stylolites in (carbonate) lithologic units. This study shows that local stresses in tectonically passive areas may allow the formation of rare oblique stylolites with peaks perpendicular to the stylolite plane. Estimation of the amount of limestone dissolved during stylolitization (minimum 7% to 12% of the depositional limestone) and the volume of sparite in the host rock (up to 1.6% of the compacted limestone) suggests that the pressure-solution fluids cemented the micropores, reducing porosity to about 10% (from a common porosity of about 40% in mechanically compacted chalk). This study thus highlights the importance of microporosity as a sink for burial cements, an observation difficult to make in thin-section. Analysis of stylolite infills at Site U1352 shows no evidence that the stylolites acted as conduits for diagenetic fluids, unless if the fluid was host-rock buffered and thus its chemistry indistinguishable from that of the host rock. The link between siliciclastic content in carbonate rocks and the spacing and amplitude of stylolites improves understanding of burial compaction processes. Predicting the morphology and spacing of stylolites in the subsurface can be used to identify baffles to cross-stylolite fluid flow or cementation (of microporosity) influencing heterogeneity of petrophysical properties in (subsurface reservoir) host rocks.

A deep knowledge of the behaviour of multi-component products for stone protection by an integrated analysis approach

The application of hydrophobic polymers to stone materials is an important treatment to preserve stone artefacts and protect cultural heritage from decay. To improve the characteristics and performance of water-repellent treatments, new solutions have been explored. In this research context, great attention has been paid to multi-component formulations that contain various monomers and copolymerise directly on stone. When they are obtained on inert rather than real substrates, such as stone, polymeric materials are often quite different in terms of their chemical and physical characteristics, polymerisation rate, and rheological properties. The stone's characteristics strongly influence its response to the application of conservation products; so different issues may be seen when applying the same treatment, depending on the interaction between the applied product and the stone support. Because of this, it is crucial to have the right tools to investigate how the substrate affects the monomers’ distribution of the applied mixtures and the resulting performance of the treatments. In this study, we followed an integrated approach based on the data collected by different analytical techniques (contact angle and colorimetric measurements, FT-IR analyses and ESEM-EDS analyses) to acquire a deeper knowledge of the behaviour of potential innovative water-repellents and their interaction with a stone support. This combined approach was used to evaluate the behaviour of methacrylate/vinyl-polysiloxane multi-component water-repellents applied on two calcareous stones displaying different microstructure and porosity: a compact limestone and a porous calcarenite.The results obtained show that the study of a multi-component mixture/substrate system by an integrated analytical approach allows one to assess the efficacy of new water-repellents and identify critical issues related to the nature of the support, providing useful information for the engineering of these chemical systems.

Neutron Activation Property of Colemanite-Peridotite Concrete

Trace element analysis using instrumental neutron activation analysis for neutron shield concrete made from colemanite and peridotite rocks is carried out. Also, an activation estimation for the concrete wall in the accelerator neutron source facility is calculated using the obtained element data. The results show that the amount of short-half-life nuclide production in the neutron shield concrete is ˜1/100 that of limestone concrete and also that the amount of 60Co production is 1/5 to 1/8 that of limestone concrete. From these results, the activation property of the neutron shield concrete was found to be much less than that of the limestone concrete, which has been previously reported as having low activation.

Influence of Crushed Basalt Aggregate on Crack Resistance of Concrete

The crack resistance of concrete with crushed basalt aggregate was studied. Compared with the limestone concrete, the basalt concrete has larger drying shrinkage and autogenous volume deformation. The linear expansion coefficient of basalt concrete is 1.3×10－6 /°C larger than that of limestone concrete, and it has additional temperature deformation of 24.1×10－6. According to the analysis on temperature-stress of concrete, the cracking temperature of basalt concrete is 8.9°C higher than that of limestone concrete, and the crack resistance of basalt concrete is unfavorable.