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The earth’s temperature gets raised to a higher level due to global warming, which creates a distressed environment for the people to survive. Geopolymer, which is intrinsically a thermal resistant building material that, can give a better solution to make a comfort zone than Ordinary Portland Cement. Geopolymer along with insulative fibre and admixture makes it more suitable for thermal application. This paper presents in detail about the results of an experimental investigation that are carried out to predict the heat resisting behaviour of flyash-based geopolymer (FG) tiles intended for thermal applications in buildings. For this purpose, several tests such as steady state temperature, furnace heat resistance, open to sky, flame resistance, heat dissipation, thermal shock resistance, thermogravimetry analysis and thermal conductivity are carried out on geopolymer tiles. From the test results, it is found that geopolymer cube prepared with 0.5% basalt fibre to the mass of mix and 0.5% titanium dioxide to the mass of flyash gives higher compressive strength of 33.10 MPa with the dry density of 1961 kg/m 3 and it shows a better thermal effect with the temperature drop of 8.4 °C. This enhancement is mainly due to the strong oxidizing property of titanium dioxide and high temperature withstanding capability of basalt fibre after undergoing high temperature processes. [ABSTRACT FROM AUTHOR]

The incorporation of plant crops in construction materials offers very good hygrothermal performance to the building, ensuring substantial environmental and ecological benefits. This paper focuses on studying the evolution of hygrothermal properties of hemp concrete over age (7, 30 and 60 days). The analysis is done with respect to two main hygric and thermal properties, respectively: sorption isotherms, water vapor permeability, thermal conductivity and heat capacity. In fact, most of these parameters are very susceptible to change function of the age of the material. This influence of the aging is mainly due to the evolution of the microstructure with the binder hydration over time and the creation of new hydrates which can reduces the porosity of the material and consequently modify its properties. All the tested hemp concrete samples presented high moisture storage capacity and high-water vapor permeability whatever the age of such hygroscopic material. These hygric parameters increase significantly for high relative humidity requiring more consideration of such variability during the modeling of coupled heat and mass transfer within the material. By the same, the thermal conductivity and heat capacity tests highlighted the impact of the temperature and hygric state of the studied material. [ABSTRACT FROM AUTHOR]

The paper presents the results obtained in the course of a study on the concrete made of aggregate obtained from wastes of sanitary ceramics. Previous examinations proved high in strength and durability of concrete of this type, and it showed a resistance to high temperatures. The material was classified as a fireproof concrete. While searching for the optimal applications of such concrete, a series of examinations and analyses on its thermal energy storage (TES) properties were performed. This paper describes the two-stage experiment on the thermal behavior of the concrete made with sanitary ceramic wastes during cooling processes in comparison to different building materials subjected to the same thermal conditions. On the basis of the thermal, infrared analysis, and suitable calculations, the thermal power and the ability of the composite to store thermal energy was estimated. Finally, it was stated that the concrete made of sanitary ceramic waste aggregate and alumina cement can be recommended as a heat-accumulating material, and in combination with high durability can be used, e.g., for the construction of fireplace bodies. [ABSTRACT FROM AUTHOR]

Pipe-embedded concrete radiant floor system has gained much popularity due to its higher energy efficiency and better thermal comfort. Simplified yet accurate heat transfer models are essential for energy simulation of this system. This study presents the development and validation of a simplified RC-network model for the pipe-embedded concrete radiant floors. A concrete radiant floor mainly consists of three parts which are the cover layer, the pipe-embedded concrete slab and the insulation layer. The cover layer and the insulation layer are simplified as one-dimensional and represented by RC models with two resistances and one capacitance (2R1C). Within the pipe-embedded concrete slab, the complex heat transfer is represented by a coupled RC model which includes two parts describing the heat transfers of the concrete slab and the water loop respectively. In the case studies, the coupled RC model for the pipe-embedded concrete slab has been validated in both numerical and experimental ways. The experimental validation results show that the average relative errors of the coupled RC model in predicting the upper and bottom surface heat fluxes are all less than 5.5%. Validation has also been conducted to demonstrate the accuracy and effectiveness of this developed simplified RC-network model in predicting the dynamic thermal performance of a multi-layer pipe-embedded concrete radiant floor. The developed simplified RC-network model can be beneficial for design and optimal control of the pipe-embedded concrete radiant floor system. [ABSTRACT FROM AUTHOR]

Our study was directed to improve the residual flexural strength and the heat-resistant properties of concrete exposed to high temperatures using different fiber cocktail loadings including steel, polymer or cellulose fibers. At first the morphology and the thermal properties of the fibers and the fiber/cement composites were investigated by SEM and TG/DTA-MS. Then the influence of fiber type and amount on residual flexural strength was tested after cooling back from 150, 500 or 800 °C temperature loadings. By adding steel, cellulose and polymer (polypropylene) fibers to cement, improvements both in post-cracking residual flexural strength and in insensitivity against explosive spalling were reached. [ABSTRACT FROM AUTHOR]

This paper presents the effect of aggregate type on high temperature resistance of self-compacting mortars (SCM) produced with normal and lightweight aggregates like expanded perlite and pumice. Silica fume (SF) and fly ash (FA) were used as mineral additives. Totally 13 different mixtures were designed according to the aggregate rates. Mini slump flow, mini Vfunnel and viscometer tests were carried out on the fresh mortar. On the other hand, bulk density, porosity, water absorption and high temperature tests were made on the hardened SCM. After being heated to temperatures of 300, 600 and 900°C, respectively, the tensile strength in bending and compressive strength of mortars determined. As a result of the experiments, the increase in the use of lightweight aggregate increased total water absorption and porosity of mortars. It is observed that, the increment in the usage of lightweight aggregate decreased tensile strength in bending and compressive strengths of mortar specimens exposed to high temperatures but the usage of up to 10% expanded perlite in mortar increased the compressive strength of specimens exposed to 300°C. [ABSTRACT FROM AUTHOR]

Results are given for development of an aluminiferous binder based on aluminothermal production slags. Binders are modified with additives based on polycarboxylate esters. Properties of the binders developed and cellular heat-resistant concretes are provided. [ABSTRACT FROM AUTHOR]

The research results on heat-resistant concrete made of mixed binding material, including Portland cement, aluminum and chrome waste, nano-technogenic raw materials in the form of sludge aluminum caustic etch are presented. The presence of aluminous component in the floured heat-resisting additive with different dimensions made it possible to bind the full calcium oxide as part of a mixed heat-resistant binder. The data on phosphate binders synthesizing is provided. The application of nano-technogenic raw materials in the form of sludge provided the completeness of the synthesizing liquid phosphate bonds process, excluding external heating. The obtained aluminophosphate bond was used in the compositions of heavy heat-resistant concrete and in the structural and chemical modification of piece ceramic refractories. The use of liquid aluminophosphate bonds in the structural and chemical modification of fireclay and high-alumina refractories instead of pure phosphoric acid has significantly increased their technical efficiency. Aluminophosphate bond application in the compositions of heat-resistant lining materials has considerably increased their physical and thermal performance. [ABSTRACT FROM AUTHOR]

The article presents a description and physical evaluation of a method of flaw detection of solid structures, for example, walls, pillars, and substructures, made of refractory materials and brick masonry using as an example an investigation of concrete structures. Using the method it is possible to perform flaw detection of concrete with different fillers, including porous fillers, for example, concrete claydite. This brings the subject of flaw detection of concrete close to that of flaw detection of brick masonry and structures made of refractory materials. The method is based on local excitation of standing waves across a wall by means of multiple shock pulses. The experimental data obtained confirm that standing waves are not excited once there is a definite number of defects present, i.e., a process of complete damping of the waves occurs. [ABSTRACT FROM AUTHOR]

Heat-resistant medium-cement concrete with calcium aluminate filler is studied. It is established that addition of carbon fiber facilitates an increase in concrete strength in compression and thermal stability. Explosive breakage only does not occur for specimens with polypropylene fiber on heating a concrete specimen at a rate of 40°C/min to 1000°C. [ABSTRACT FROM AUTHOR]

Results are provided for a study of the properties of a cement matrix of medium-cement heat-resistant concrete with deflocculant additions, i.e., sodium tripolyphosphate and polycarboxylate ester. The effect of amount of deflocculant and heat treatment temperature on the change in matrix hydration product composition after hardening at 20°C and drying at 60, 80, and 110°C is considered. Comparative analysis is performed for the change in concrete physicomechanical properties and their heat resistance is evaluated in relation to amount and type of deflocculant. [ABSTRACT FROM AUTHOR]

With a different exposure temperature within concrete based on alumina cement there is formation of different hydrated phases, i.e., amorphous or crystalline AH, crystal hydrates CAH, CAH, and CAH. In developing or modifying refractory concrete composition it is necessary to consider the effect of holding temperature on concrete structure formation and operating properties. Properties are studied for traditional heat-resistant concrete, modified with addition of micro-alumina, and that based on a chamotte filler with aluminate cement grade Gorkal 70 with holding temperatures of 10, 20, and 30°C. The effect of differences in concrete structure formation with maturity over 48 h is studied by an ultrasonic method. It is established that differences in structure formation during concrete maturity affect concrete properties after firing at 1100 and 1200°C. [ABSTRACT FROM AUTHOR]

Persönliches: 'Stets auf der Suche nach den Grenzen' - Werner Sobek erhält am 8.11.2013 die Ehrendoktorwürde der TU Graz Nachrichten: Ulrich Finsterwalder, Tagung zu Person und Werk im Deutsche Museum München 1.10.2013 ( Hartwig Schmidt, Karlsruhe) Professor Hennecke als Präsident der Bundesanstalt für Materialforschung und -prüfung verabschiedet Deutscher Brückenbaupreis 2014: Sechs Brücken in der engeren Wahl. Bauwerke in Berlin, Hamburg, Thüringen, in der Oberpfalz, Backnang bei Stuttgart und Bamberg gehören zu den landesweit schönsten Brücken Wenn Konstruktiver Betonfertigteilbau, dann FDB! Die Mitgliederversammlung 2013 in Weimar spricht FDB-Vorstand und Geschäftsführung ihr volles Vertrauen aus VBI gibt Übersetzung des FIDIC 'Gold Book' heraus. International anerkanntes Vertragsmuster für Planen, Bauen und Betreiben aus einer Hand übersetzt und umfassend erläutert - Arbeitshilfe für den deutschsprachigen Anwender VBI und DEGES vereinbaren 'Leitlinien zum Projektumgang'. Leitlinien definieren Regeln für faire Zusammenarbeit von Auftraggeber und Auftragnehmer. Verbesserung der Planungskultur bei Verkehrsprojekten angestrebt DBV-Heft 27 'Wartung und Instandhaltung von Parkbauten' DBV-Heft 28 'WU-Bauweisen - Weiße Wannen und Weiße Dächer' 'Gustave Magnel Gold Medal' Award 2009-2014 Bücher: David P. Billington: 'Der Turm und die Brücke - Die neue Kunst des Ingenieurbaus'. ( Annette Bögle, Nils Ratschke und Sabrina Gieron, Hamburg) Dank: Wie immer zum Jahresende bedankt sich die Redaktion an dieser Stelle bei allen Lesern und Autoren. Besonders gedankt sei den zahlreichen Fachleuten, die der Redaktion ehrenamtlich als Rezensenten für die eingereichten Manuskripte zur Verfügung stehen. [ABSTRACT FROM AUTHOR]

A comparative study is provided for the effect of microsilica additive and one based on metakaolin on hydration of alumina cement and cement stone structure formation after hardening and firing. It is established that in a composite with alumina cement an additive based on metakaolin promotes transfer of cement minerals into solution more rapidly than microsilica additive, and also that composite hydration with additive based on metakaolin proceeds more rapidly than a composite with microsilica. Additive based on metakaolin compared with microsilica improves mechanical properties of heat-resistant concrete based on a chamotte filler: after hardening and firing the ultimate strength in compression for specimens with additive based on metakaolin is higher by 5 – 27% than this index for specimens with microsilica additive. [ABSTRACT FROM AUTHOR]

In this research, the effects of some parameters on the heat of hydration for two concrete mixes have been studied. The mixes are with and without 15% micro silica as a cement weight replacement designated (M2) and (M1) respectively, and Three concrete mixes by weight namely, (1:2:4 , 1:1.5:3 , and 1:1:2) at uniform consistency that is a constant slump of (75-100 mm) for both(M1) and (M2), and Two curing methods, moist and air cured, While the internal temperature for the specimens was measured for (28) days : at the 1st two days at intervals of half an hour then at intervals of (3 hrs) for the 3rd and 4th day, while at intervals of (6 hrs) until (28) days. The results of the research proved that the heat of hydration was higher at the 1st day than that at the 2nd day, fluctuating during the 1st (48 hrs) . The fluctuation reduces gradually to a steady rate at later ages, While the heat of hydration for all mixes and at all ages (except the 1st day) was higher for air cured specimens than that moist cured for same condition, As the cement content increased the heat of hydration (for mixes M1) increased accordingly and also the addition of silica lowered the internal concrete temperature for M1 mixes (at high and moderate cement contents) in opposite of few cement contents. [ABSTRACT FROM AUTHOR]

Abstract: In the present work attempt has been made to estimate the shielding parameters of the new serpentine concrete (density=2.4g/cm3) using local materials on the shielding parameters for two types of heat resistant concretes, namely hematite–serpentine (density=2.5g/cm3) and ilmenite–limonite (density=2.9g/cm3). Shielding parameters for ordinary concrete (density=2.3g/cm3) were also discussed. These parameters were determined experimentally for serpentine concrete and compared with previously published values for other concretes, which had also been obtained using local materials. The leakage spectra of reactor fast neutrons and total gamma photon beams from cylindrical samples of these concrete shields were also investigated using a collimated beam from ET-RR-1 reactor. A neutron–gamma spectrometer was used in order to obtain pulse height spectra of reactor fast neutrons and the total gamma rays leakage through the investigated concrete samples. These spectra were utilized to obtain the energy spectra required in these investigations. Removal cross section ΣR (En ) and linear attenuation coefficient μ(Eg ) for reactor fast neutrons and total gamma rays and their relative coefficients were evaluated and presented. Measured results were compared with those previously measured for other concretes. The results show that ilmenite–limonite concrete is a better reactor biological shield than the other three concretes. Serpentine concrete under investigation is a better reactor fast neutrons shield than ordinary and hematite–serpentine concretes. Serpentine concrete has a lower attenuation properties than the other three concretes as a reactor total gamma rays shields. [Copyright &y& Elsevier]

This investigation studied the retempering technique of remediation to mitigate the influence of combined transportation time and extreme hot and cold temperatures on plastic self-consolidating concrete (SCC). This method of remediation consisted of adjusting admixture dosage at the end of hauling to produce a matrix with similar fresh properties as those of the control concrete prepared at the temperature of 21°C and transportation duration of 10 minutes. Seven different temperatures (43, 36, 28, 21, 14, 7, and -0.5°C) and five different hauling times (10, 20, 40, 60, and 80 minutes) were adopted. Polycarboxylate-based high-range water-reducing admixture (HRWRA) and viscosity-modifying admixture (VMA) were used to produce the selected matrices with slump flow of 635±25 mm or 711±25 mm, visual stability index (VSI) of 0 (highly stable concrete) and T50 of 2 to 5 s. Laboratory test results revealed that the retempering method of remediation was successful in mitigating the adverse effect of combined hauling time and temperature on the flow characteristics of self-consolidating concrete. [ABSTRACT FROM AUTHOR]

This article describes heat-resistant thermally insulating concrete mixtures and products with phosphate and aluminate binders, their properties, and the main processes used to make them. The thermophysical properties required of thermal insulation are obtained together with an increase in its strength thanks to the production of denser but less heat-conducting concretes with fillers composed of aluminum microspheres. [ABSTRACT FROM AUTHOR]

Differences are demonstrated in hydration of high-alumina cements, produced in the Gor'ka Plant (Poland), in the presence of both individual and composite deflocculants. Properties are provided for medium-cement heat-resistant concrete with a composite deflocculant in relation to cement type. [ABSTRACT FROM AUTHOR]

The use of concrete filling offers a practical alternative for achieving the required fire resistance in steel hollow structural section (HSS) columns. However, the current prescriptive-based approach has a number of constraints that in many applications restrict the utilization of concrete filling for achieving the required fire resistance. To overcome such constraints, a performance-based methodology for fire resistance design is presented in this paper. A set of numerical simulations were carried out to investigate the effect of realistic fire scenarios, loading and stability-based failure criterion on the fire resistance of concrete-filled HSS columns with lengths ranging from 3.8 m (12.5 ft) to 10 m (32.8 ft). It is demonstrated that by adopting a performance-based approach, it is possible to achieve the required fire resistance in CFHSS columns in most practical situations. [ABSTRACT FROM AUTHOR]

Abstract: This study explores the influence of olive waste ash (OWA) on the performance of concrete exposed to elevated temperatures in the range from 400 to 600°C. The performance of concrete to elevated temperature was evaluated using compressive strength and electrical charge of concrete. Three OWA levels were used in the study: 7%, 15%, and 22% by weight of cement. The other experimental parameters investigated in the study were elevated temperature (400 and 600°C), aggregate type (crushed basalt and volcanic tuff), w/c ratio (0.5 and 0.7), and air content (non-air and air entrained). After the initial moist curing period of 90 days, concrete specimens were exposed to elevated temperatures for a period of 2h using an electric furnace. The study showed that the performance of OWA concrete to elevated temperatures is higher than that of the control concrete. Additionally, the performance of OWA concrete to elevated temperature increased when the OWA content was increased. The resistance of OWA concrete containing tuff aggregate to elevated temperatures was observed higher compared to OWA concrete containing basalt aggregate. The OWA concrete at w/c ratio of 0.5 was found to be more resistant to elevated temperatures than that of OWA concrete at w/c ratio of 0.7. The performance of the air entrained OWA concrete to elevated temperature was observed higher compared to the non-air entrained OWA concrete. [Copyright &y& Elsevier]

Tests simulating “the accidental conditions” and the “test of heating,” without the contribution of humidity, have been carried out on test equipment that we designed and fabricated in the scope of this work. The tests have been carried out on laterally sealed and insulated cylindrical specimens of ordinary or high-performance concrete having a thickness of 1.3 m. Experimental results present temperature, pressure, and moisture distribution throughout the specimens and permit to characterize the hygrothermal behaviour of a concrete wall. The different aspects of the phenomena affecting a two-phase transfer (steam, water) in a porous medium are presented. Test results show that high-performance concrete exposed to an increase in temperature presents a particular hygrothermal behaviour, because of its microstructure, that is put into evidence, notably while looking at the role of the silica fume. The migration of water is not as rapid in high-performance concrete as in ordinary concrete, which is favourable for tightness. Numerical investigation consists of adapting a heat and mass transfer model, initially built for ordinary concrete, to the high-performance concrete used in this work. [ABSTRACT FROM AUTHOR]

An efficient numerical approach using the Green’s function solutions of transient heat conduction for predictions of thermal response inside a concrete-filled rectangular hollow section subjected to fire is proposed in this paper. Thermal properties of construction materials are assumed to be isotropic and homogeneous. The Green’s function approach adopts different series expansions for small and large time solutions, therefore the desirable convergence properties can be achieved at any range of time by using the time partitioning strategy. A useful analytical relation in terms of step Green’s functions is derived in this paper to incorporate the multidimensional effect, in particular, for Neumann (prescribed flux) boundary conditions. A modified lumped capacitance method, together with an “orthogonal flux” concept, are employed to deal with spatially varying heat flux at the steel–concrete interface, where Duhamel’s theorem is applied in piecewise manner along the interface to incorporate the fire boundary conditions. No spatial discretization is required in the numerical algorithms based on the Green’s function approach. [ABSTRACT FROM AUTHOR]

The NPF Alineka company has developed refractory construction concretes BRSB20I11 based on water glass and concretes BRAB50I13 and BRAB50I15 with the traditional content of aluminate cement, which have a high class of thermal resistance (T140–T180) and the maximum application temperature of 1100–1500°C, as well as heat-insulating lightweight plates of size 300 × 200 × 80 mm and density 400 kg/m3, with a maximum application temperature of 1150°C. These materials can be used as lining of tunnel furnace cars for firing wall ceramics, as well as porcelain and faience products. The experience in repairing a furnace car is described. [ABSTRACT FROM AUTHOR]

The authors describe the results of studying medium-cement heat-resistant concrete with an additive of waste catalyst (WC) that is generated at oil-processing plants and compare them with traditional microsilica and reactive alumina additives. Certain specifics of reactions between aluminate cement Gorkal-40 and the WC are identified, which accelerate the setting and hardening of concrete. The WC additive facilitates the formation of anorthite in the concrete matrix, which has a positive effect on the thermal resistance of heat-resistant concrete. [ABSTRACT FROM AUTHOR]

It is noted that methods for choosing the composition of refractories and structural concretes differ significantly. In choosing refractory concrete composition physicochemical processes occurring during hardening and sintering should be considered. It is established that the most complete requirements are satisfied by concretes based on high-alumina cement and corundum filler. [ABSTRACT FROM AUTHOR]

Composite binder is prepared in the system NaO-MgO-SiO. Due to its production advantages it may serve as a basis for manufacturing high quality ceramic concretes based on periclase that may be used successfully for lining heating units in metallurgy and the building material industry. [ABSTRACT FROM AUTHOR]

Nanoparticles of SiO2 or TiO2 have been added in the preparation of heat-resisting concretes of two types. The major technical and chemical characteristics have been determined. Features have been found in some of the technological operations in making the concretes of both types, and also aspects of the physicomechanical properties. Higher chemical stability has been found for heat-resisting concrete containing TiO2 nanoparticles in an NaOH solution. [ABSTRACT FROM AUTHOR]

Aluminosilicate ceramoconcrete lining for cars used in ceramic plant firing kilns was developed and introduced. The first cars with this lining have already operated for more than 50 cycles. [ABSTRACT FROM AUTHOR]

Fine β-sialon (Si6− zAl zO zN8− z, 1< z<4) was prepared by mechanical-activated combustion synthesis (CS) using raw materials such as Si, Al, and SiO2 in a nitriding atmosphere of 1 MPa. Mechanical activation by planetary milling for only 18 min led to the formation of β-sialon after combustion synthesis. Comparative experiments with ball milling showed that the relative amount of β-sialon was considerably increased to 66% when planetary milled to 18 min after CS. The raw material Si was replaced by waste Si of 94.8 mass% in purity, and was combustion synthesized successfully under the same processing parameters for cost-effective measures. [ABSTRACT FROM AUTHOR]

This article examines aspects of the production of heat-resistant concretes and products made of them at ISPAT-Karmet by using recycled refractories. Most of these products are used in the lining of soaking pits. The products are comparable to imported refractories in terms of durability. [ABSTRACT FROM AUTHOR]

It is noted that the reinforcing components is distributed quite uniformly within concrete. Adhesion with binder is strong. Under action of high temperature there is active conversion of raw material fibers into corundum with an increase in volume. The material created surpasses unreinforced concrete with respect to strength properties and thermal shock resistance, and is distinguished by good volume constancy during operation. [ABSTRACT FROM AUTHOR]

Corundum reinforced concrete, whose resistance is estimated as good in carbon- and hydrogen-containing atmospheres, may be recommended for operation at any temperature below the permissible limit. Objects also demonstrate good resistance in a strongly reducing atmosphere. [ABSTRACT FROM AUTHOR]

Mathematical planning of an experiment is used to determine optimum relationships between fractions of filler, high-alumina cement, and mixing water in corundum concrete. Characteristics of density, ultimate strength in compression, and concrete structural quality factor are obtained. [ABSTRACT FROM AUTHOR]

Zum Titelbild Beim Einsatz von Ultraschallecho-Methoden in der zerstörungsfreien Prüfung im Bauwesen stellt die Untersuchung von Spannbetonkonstruktionen eine der anspruchsvollsten Aufgaben für Wissenschaft und Technik dar. Das inhomogene Gefüge aus Beton, schlaffer Bewehrung und Spanngliedern erfordert eine Optimierung von Messtechnik und Auswertesoftware, um verwertbare Aussagen zum Verpresszustand der Hüllrohre zu erhalten. Auf dem Titelfoto ist eine Spannbetonbrücke zu sehen, bei der im Rahmen einer praktischen Anwendung die Lage eines Hüllrohrverstopfers lokalisiert und die Ausdehnung der Blockadestelle eingegrenzt werden konnte, wie im Beitrag auf Seite 845-853 gezeigt wird. Zudem werden die Grundlagen der bildgebenden Darstellung von US-Echo-Daten sowie die Untersuchung und Datenauswertung an Probekörpern beschrieben. (Foto: Sebastian Schulze) [ABSTRACT FROM AUTHOR]

The section of "Industrial Applications of Textiles," focuses on civil engineering applications of fabrics. Holland has been developing fabrics for the reinforcement of bituminous roads. A fabric layer can be laid on the top of sand while constructing road, which provides good adhesion; resistance to humidity, rotting, and ageing; resistance to the conditions of road-building; and a good modulus of elasticity and strength. To increase the cracking resistance of sand-asphalt mixtures, glass fibres have been used.