Showing papers in "Cement and Concrete Research in 2015"

TL;DR: Alkali activation is a highly active and rapidly developing field of activity in the global research and development community as discussed by the authors, and commercial-scale deployment of alkali-activated cements and concretes is now proceeding rapidly in multiple nations.

TL;DR: In this paper, the growth of C-S-H is the principal factor controlling the main heat evolution peak and after several days space becomes the major factor controlling hydration, but deceleration cannot be attributed to diffusion control.

TL;DR: A review of the advances in knowledge provided by research in these areas can be found in this paper, emphasizing the impact of the research on the field and emphasizing the benefits of these advances.

TL;DR: In this paper, a wide range of alternative approaches to the reduction of CO 2 emissions associated with the manufacture of the binder phase in concrete are discussed, and they are classified broadly as follows: (1) Use alternative fuels and/or alternative raw materials in the manufacturing of Portland-based cements.

TL;DR: In this article, the authors summarize the current state of understanding and the existing knowledge gaps with respect to reaction mechanisms and the roles of aggregate properties (e.g., composition, mineralogy, size, and surface characteristics), pore solution composition, pH, alkalis, calcium, aluminum, and exposure conditions, such as temperature, humidity) on the rate and magnitude of alkali-silica reaction.

TL;DR: In this article, the authors reviewed and discussed recent research activities on the durability of concrete, including: 1) major durability problems such as alkali aggregate reaction, sulfate attack, steel corrosion and freeze-thaw; 2) concrete in marine environment; and 3) coupling effects of mechanical load and environmental factors on durability.

TL;DR: In this paper, the absorption capacity of a solution-polymerized superabsorbent polymers (SAP) was first determined on hardened cement pastes by SEM image analysis, and it was observed that the SAP cavities become partially filled with portlandite during cement hydration.

TL;DR: In this paper, a review on the relationship between the composition, the structure and the solution in which calcium silicate hydrate (C-S-H) is equilibrated is presented.

TL;DR: In this article, the effect of aluminium uptake in C-S-H was investigated in the presence and absence of alkalis on the composition and the solubility of a C S-H with a Ca/Si equal to 1.0, where the presence of potassium hydroxide leads to higher pH values, to the destabilisation of stratlingite and to higher dissolved aluminium concentrations.

TL;DR: In this paper, a comparative study of NSF and PCE superplasticizers was carried out aiming at correlating the adsorption in fresh cement pastes (fcps) with their dispersing capability and the impacts on cement hydration.

TL;DR: In this article, the authors showed that the amount of solid carbonates and of carbonate ions in a hydrous environment increases with increasing Ca/Si ratio for the C-S-H, as shown by 13 C NMR.

TL;DR: In this article, the effect of temperature on the structure and solubility of calcium aluminosilicate hydrate (C-A-S-H) was investigated.

TL;DR: In this article, the authors determined the autogenous shrinkage of fly ash and blast-furnace slag containing binders using both manual and automated shrinkage measurements and showed that internal curing by means of superabsorbent polymers is successful, independent of this long term higher rate of shrinkage in mixtures with supplementary cementitious materials.

TL;DR: In this paper, the degradation mechanisms of natural fiber in the alkaline and mineral-rich environment of cement matrix are investigated by designing a contrast test to embed sisal fibers in pure and metakaolin modified cement matrices.

TL;DR: In this article, the transport properties of cement mortar with graphene nanoplatelet (GNP) were investigated experimentally in the presence of a low cost carbon-based nano-sheet, which was added to mortar at contents of 0, 2.5, 5.0 and 7.5%.

TL;DR: In this article, the impacts of the charge characteristics of polycarboxylate (PC) co-polymers on their adsorption behaviors and the retardation effects on cement hydration were investigated.

TL;DR: In this article, a short dispersion route using Pluronic F-127 as a novel dispersing agent was used to develop carbon nanotube (CNT) reinforced cement composites.

TL;DR: In this article, the effect of SCM in the cement paste was isolated by using ternary systems combining Portland cement, quartz and SCM, and the results showed clear differences in how the hydrates from the reaction of clinker, slag, and fly ash fill space.

TL;DR: In this paper, the compressive behaviour of recycled aggregate concrete (RAC) with different recycled coarse aggregate (RCA) replacement percentages was experimentally investigated under quasi-static to high strain rate loading.

TL;DR: In this paper, the first definitive evidence that dissolution of the glassy aluminosilicate phases of both fly ash (FA) and ground granulated blast furnace slag (GBFS) occurred under the pH conditions of MKPC was presented.

TL;DR: In this paper, the authors used the standard RILEM pull-out test to assess the development of the bond strength from 24h to 28 days after casting, with different heat curing conditions.

TL;DR: In this paper, the effect of the addition of graphene nanoplatelets (GNPs) on the microstructure and mechanical properties of a fly ash based geopolymer was reported.

TL;DR: In this paper, the authors present experimental results on the different hydration states of the most important AFm phases: monocarboaluminate, hemicarbo alumininate, stratlingite, hydroxy AFm and monosulfo aluminate and the thermodynamic properties associated with changes in their water content during absorption/desorption.

TL;DR: In this article, the pore structure of leached cement pastes was studied from micro-scale down to the nano-scale by combining micro- and nano-X-ray computed tomography (micro- & nano-CT).

TL;DR: In this article, the incorporation of in-situ reduced graphene oxide (rGO) into geopolymers was reported for the first time, and the resulting rGO-geopolymeric composites are easy to manufacture and exhibit excellent mechanical properties.

TL;DR: In this article, a review of measuring devices and transformation equations used to express rheological parameters in fundamental units is presented, and some of the major issues that can lead to errors during the interpretation of rheology measurements are discussed.

TL;DR: In this paper, the rheological properties of fresh, cement-based mortars modified with superabsorbent polymers (SAPs) were investigated for 90min by continuous flow rheometry.

TL;DR: In this article, the C-S-H molar volume evolution during fly ash-blended cement carbonation was calculated using a method combining MIP, TGA and GRAM.