Showing papers in "Cement and Concrete Research in 2006"

TL;DR: In this paper, a thermodynamic model is developed and applied to calculate the composition of the pore solution and the hydrate assemblage during the hydration of an OPC.

TL;DR: In this article, the methods used to measure and model thixotropy of fresh concrete in the civil engineering field are described and a simple thixotropic model is presented, which is in agreement with the experimental observations that can be found in the literature.

TL;DR: In this article, the influence of fiber diameter, length and geometry on plastic shrinkage cracking in concrete was investigated using four commercially available polypropylene fibers at dosage rates varying from 1% to 3%.

TL;DR: In this article, the authors used thermal gravimetric analysis (TGA) and X-ray diffraction analysis (XRDA) to determine the intensity distribution of Ca(OH)2 and CaCO3.

TL;DR: In this paper, the authors present a study of the evolution of indexes related to hydration and their correlation to the development of the mechanical properties for an Ultra-High Performance Fiber Reinforced Concrete (UHPFRC).

TL;DR: In this article, a study of thermal stability of properties upon firing at 800-1200°C of geopolymer materials prepared using class F fly ash and Na and K alkaline activators was performed.

TL;DR: In this paper, a field trial was conducted using a 40 MPa concrete mixture, incorporating various proportions of glass powder (0, 20, and 30%) as cement replacement, and the results demonstrated that GLP can be incorporated into 40MPa concrete at dosage rates of 20-30% to replace cement without harmful effects.

TL;DR: In this paper, X-ray diffraction, compositional analysis, and 27Al MAS NMR spectroscopy of Alsubstituted tobermorite-type C�S�H made by precipitation from solution provide significant new insight into the structural mechanisms of Al-substitution in this important and complicated phase.

TL;DR: In this article, an experimental research was performed on the complete compressive stress-strain relationship for concrete after heating to temperatures of 100-800 °C, where the shape varying with temperature was considered.

TL;DR: In this paper, a technique to segment pores from a normal backscattered electron (BSE) image of cement-based materials is presented, where the upper threshold grey level for porosity is determined from the inflection point of the cumulative brightness histogram of the BSE image.

TL;DR: The strength development of mortars containing ground granulated blast-furnace slag (ggbs) and portland cement was investigated in this paper, and the apparent activation energies were determined according to ASTM C1074 and were found to vary approximately linearly with ggbs level.

TL;DR: In this article, the compressive strength, flexural strength, elastic modulus and porosity of concrete reinforced with 1% steel fibre and changes of colour to the heated concrete have been investigated.

TL;DR: In this paper, the effect of metakaolin replacement of cement on the durability of concrete to sulfate attack was investigated by measuring expansion of concrete prisms, compressive strength reduction, and visual inspection of concrete specimens to cracks.

TL;DR: In this article, the Densified Mixture Design Algorithm (DMDA) was applied in the design of High Performance Concrete (HPC) to have a slump of more than 180 mm and a slump-flow larger than 550 mm.

TL;DR: In this article, optical microscopy is also used for damage diagnosis of degraded historic mortars and for the study of the interfacial zone, the bonding and possible reaction rims between aggregates, bricks or stone and the mortar.

TL;DR: In this paper, an efficiency concept is proposed in order to take into account the effect of mineral admixture in mortars from both the physical and chemical points of view, using an efficiency function ξ(p) that has notable properties: it is independent of time, independent of fineness and independent of the type of mineral mixture.

TL;DR: In this paper, the effects of decalcification under saturated conditions on the dimensional stability of cement paste were investigated, and it was found that the decalcation shrinkage is due initially to these structural changes in C3S-H at Ca/Si ´1.2 and eventually to the decomposition of C−S−H into silica gel.

TL;DR: In this paper, the relationship between explosive spalling occurrence and residual mechanical properties of fiber-toughened high-performance concrete exposed to high temperatures was explored, including compressive strength, tensile splitting strength, and fracture energy.

TL;DR: In this paper, a simple model is proposed to relate ultrasonic pulse velocity with porosity and permeability, and experimental results are shown and correlations between the measured parameters of the material are discussed.

TL;DR: In this article, it was shown that the resonance originates from an amorphous or disordered aluminate hydrate which contains Al(OH) 6 3− or O x Al( OH) 6- x (3+ x )− units.

TL;DR: Rubberized self-compacting concrete was prepared containing different amounts of untreated tyre waste and their mechanical and microstructural behaviour were investigated and discussed in this article. But their results were limited.

TL;DR: The properties, structure, and behavior of cement paste, including surface area, drying shrinkage, creep, and permeability are discussed with the assumption that the C-S-H gel is an aggregation of precipitated, colloidal-sized particles that undergoes chemical aging as discussed by the authors.

TL;DR: In this article, the influence of powder materials on self-compactability, viscosity and strength were compared with a properly designed set of test methods (the mini-slump, V-funnel tests, viscoity measurements and compressive strength tests).

TL;DR: In this article, the porosity and physical features of the pore network were characterized using Electrical Impedance Spectroscopy (EIS), which was found to be an inaccurate indicator of the electrical conductivity of the sample.

TL;DR: In this article, the authors present the experimental results and prediction model for the autogenous shrinkage of concrete made with various water-to-cementitious materials ratios (w/cm) ranging from 0.27 to 0.42 and granulated blast-furnace slag (BFS) in the range of 0% to 50% by mass of the total cementitious materials.

TL;DR: In this paper, the authors analyzed the effect of the amount of polypropylene (PP) fibers on the spalling behavior of normal-strength in-situ concrete without and with PP-fibers (1.5 kg/m3).

TL;DR: In this paper, the effectiveness of three organic commercial inhibitors in preventing carbon steel chlorides induced corrosion in concrete is investigated, since there is not yet a clear knowledge on the real effectiveness of these products.

TL;DR: In this article, the properties of concretes containing various waste E-glass particle contents were investigated in a study, where the size distribution of cylindrical glass particle was from 38 to 300 {mu}m and about 40% of Eglass particle was less than 150 µm, and the workability decreased as the glass content increased due to reduction of fineness modulus.

TL;DR: In this article, a relationship between the yield stress and slump cone was found to depend on the volume fraction of matrix used in the concrete mixture, and a low correlation between the slump cone and plastic viscosity was found.

TL;DR: In this article, a servo-hydraulic testing machine was used to study the strain-rate dependent behavior of concrete in tension and the effect of temperature and moisture content on the strain sensitivity of concrete.