Showing papers in "Cement and Concrete Research in 2016"
••
TL;DR: In this paper, the authors introduced a new rapid, relevant and reliable (R 3 ) test to predict the pozzolanic activity of calcined clays with kaolinite contents ranging from 0 to 95%.
296 citations
••
TL;DR: In this paper, the physical and chemical changes of alkali-activated slag (AAS) after a prolonged drying treatment under various relative humidity (RH) conditions were studied, and the shrinkage kinetics of AAS is strongly dependent on the RH, but irrespective of the moisture loss.
252 citations
••
TL;DR: In this paper, a stoichiometrically-controlled alkali-activated pastes containing calcium-sodium aluminosilicate hydrate (C-(N)-A-S-H) and sodium aluminosa-aluminosileic hydrate gels are produced by alkali activation of high-purity synthetic calcium aluminosity powders.
219 citations
••
TL;DR: In this article, a rearrangement of the C-A-S-H structure was found to result in shorter silica chains and less calcium is present in the interlayer.
209 citations
••
TL;DR: In this article, Na 2 CO 3 -activated slag cements were produced from four different blast furnace slags, each blended with a calcined layered double hydroxide (CLDH) derived from thermally treated hydrotalcite.
206 citations
••
TL;DR: In this article, the molar mg/Si ratios of synthetic magnesium silicate hydrate (M-S-H) samples were investigated for 1-year and it was shown that M-SH aged for 1 year can exhibit variable compositions with molar Mg/si ratios in the range 0.7 ǫ ≪ 1.5 Ǫ ≪ 0.5.
203 citations
••
TL;DR: In this paper, the pore structure was inferred using mercury intrusion porosimetry and significant reduction in pore sizes was measured, and the barrier effects of GNP were characterized and it was found that more than 50% of the improvement in transport resistance can be attributed to tortuosity while the rest to pore refinement.
201 citations
••
TL;DR: Aluminum uptake in calcium silicate hydrate (C-S-H) was studied at different Ca/Si ratios from 0.6 to 1.6 at 20°C.
198 citations
••
TL;DR: Parallel corrosion experiments were carried out for 2¼ years by exposing one half of 210 beam specimens (120.5 × 130 × 375 mm long) to accelerated laboratory corrosion (cyclic wetting and drying) while the other half underwent natural corrosion in a marine tidal zone.
182 citations
••
TL;DR: In this article, the effects of limestone filler (LF) and slag (GGBS) on chloride migration and water absorption of concretes with systematically varied aggregate properties were evaluated from the view point of ITZ by using BSE image, EDS, and MIP analysis.
178 citations
••
TL;DR: In this article, the potential of superabsorbent polymers (SAPs) to self-seal such cracks was investigated via transport experiments, microscopy and modelling, and the results showed that SAP can re-swell and seal cracks, for example in the case of 0.3 mm cracks reducing peak flow rate and total flow by 85% and 98% respectively.
••
TL;DR: In this article, the authors investigated the effects of the belite content and carbonation curing on the physicochemical properties of cement mortar and showed that a higher alite content in cement increases CO2 uptake during the carbonation-cured process and thus promotes microstructural densification.
••
TL;DR: In this article, the carbonation of Portland cement, metakaolin and limestone mortars has been investigated after hydration for 91 days and exposure to 1% (v/v) CO 2 at 20°C/57% RH for 280 days.
••
TL;DR: In this paper, the physicochemical properties of binder gel in alkali-activated fly ash/slag exposed to high temperatures were investigated, and the porosity under high temperatures had an inverse relationship with the strength.
••
TL;DR: In this article, the compressive strength of steel slag pastes and slag-PC pastes was investigated under CO2 curing for up to 14 d. The results showed that the mechanical strength augments were mainly attributed to the formation of calcium carbonate, which caused microstructure densification associated with reducing pore size and pore volume in the carbonated pastes.
••
TL;DR: In this article, an investigation of the recycled concrete microstructure using synchrotron microtomography (μCT) at the Advanced Light Source combined with Scanning Electron Microscopy analysis was performed.
••
TL;DR: In this article, the performance of chloride-contaminated reinforced GPC specimens manufactured using a blended low-calcium fly ash and slag cement is investigated by long-term monitoring of corrosion parameters such as open circuit corrosion potential, polarization resistance and Tafel slopes.
••
TL;DR: In this article, the hydration of four sulfoaluminate cements have been studied: three sulfo aluminate systems, having different content of sulfate and silicate, and one blend Portland-CSA-calcium sulfate binder.
••
TL;DR: In this article, the kinetics and products of silica glass dissolution are studied as a function of solution pH, temperature, and availability of calcium, and it was observed that dissolution rate versus time increases linearly with pH and reaches a maximum at pH = 14, with slower dissolution at higher alkalinities.
••
TL;DR: In this article, the authors show that the undersaturation with respect to C3S always increases when C 3S hydration enters into the deceleratory phase, leading to the conclusion that C 3 S dissolution is at the origin of this deceleration, not C S H growth.
••
TL;DR: In this article, the effect of three common retarders (sodium gluconate, sodium-potassium tartrate and borax) on early-age hydrate assemblages was investigated.
••
TL;DR: Alkali-activated and cementitious mortars were tested and compared in terms of workability, dynamic modulus of elasticity, porosimetry, and water vapor permeability as discussed by the authors.
••
TL;DR: A comprehensive overview of existing experimental and modelling approaches to determine effective diffusion coefficients of water saturated ordinary Portland cement-based materials can be found in this article, where a dataset for diffusivity obtained from different experimental techniques have been presented for cement paste, mortar and concrete.
••
TL;DR: In this paper, the influence of triethanolamine (TEA) on the portlandite in hardened cement pastes (HCPs) was systematically investigated and it was shown that TEA can significantly alter the morphology of CH crystals and even the content of the crystalline CH phase.
••
TL;DR: In this paper, the pore size distribution in mature cement pastes following one and two cycles of drying and rewetting is studied using 1H nuclear magnetic resonance (NMR) relaxometry.
••
TL;DR: In this paper, the influence of fibres on the main parameters governing corrosion of conventional reinforcement has been discussed and a literature review summarises the influence that fibres have on the performance of reinforced concrete.
••
TL;DR: In this paper, a selection of experimental results of creep tests found in the scientific literature are used to highlight the nonlinearity, multi-axiality, hydration, and thermal and drying effects.
••
TL;DR: In this paper, a large collection of microstructural studies on concretes exposed to marine environments for periods between 2 and 34 years was presented. And the phase changes were studied using optical as well as scanning electron microscopy.
••
TL;DR: An experimental approach based on the study of the pore solution of metakaolin-based geopolymer has been established in this article to investigate the phenomenon of carbonation in these materials.
••
TL;DR: In this article, the effect of physical, crystallographic and chemical characteristics of fly ash on geopolymerisation performance and the strength of the resulting binders is assessed. But the authors do not consider the impact of fly ashes on the performance of the final product.