Advances in Cement Research 

About: Advances in Cement Research is an academic journal published by Thomas Telford Ltd.. The journal publishes majorly in the area(s): Cement & Portland cement. It has an ISSN identifier of 0951-7197. Over the lifetime, 1068 publications have been published receiving 19571 citations. The journal is also known as: ACR.

Alkali-activated slag cement and concrete: a review of properties and problems

Abstract: This paper summarizes the advantageous and disadvantageous properties of alkali-activated slag cement and concrete by reviewing previously published work in English, Russian and Chinese. Practical problems and theoretical questions are discussed. Topics for future work in this field are suggested. The practical problems mentioned are quick setting, the possibility of alkali—aggregate reaction, and the occurrence of efflorescence, shrinkage, microcracks and strength variation. The theoretical questions discussed concerning alkaline activation include the roles of the alkaline anion and cation, the nature of the hydration products, microstructural development and the setting and hardening mechanisms.

Surface decoration of carbon nanotubes and mechanical properties of cement/carbon nanotube composites

Abstract: The present study investigated the effects of the method of surface decoration on the wetability of multi-walled carbon nanotubes (MWCNTs) and the mechanical properties of the cement paste incorporating these dispersions. The results showed that stable and homogenous dispersions of MWCNTs in water can be obtained by using surface functionalisation combined with decoration using polyacrylic acid polymers. The cement paste specimens incorporating these dispersions revealed good workability and an increase in the compressive strength of nearly 50% even with only a small addition of the MWCNTs, namely 0·045–0·15% of the cement weight. These results indicate the existence of chemical bonds between the OH groups of the functionalised MWCNTs and probably the CSH phase of the cement matrix, which enhanced the transfer of stresses. A second method that was studied included decoration of MWCNTs with polyacrylic acid polymers and gum Arabic. These dispersions appeared to be homogeneous only for approximately 2 h aft...

Hydration of alkali-activated slag: comparison with ordinary Portland cement

Abstract: A multi-method approach was used for the investigation and comparison of alkali-activated slag binders (AAS), pure slag and ordinary Portland cement (OPC). X-ray fluorescence, X-ray powder diffraction, granulometry, calorimetry, thermo-gravimetric analysis and environmental scanning electron microscope investigations of the microstructure with energy dispersive X-ray analyses were used to characterise the cements and their hydrate phases. In addition, the chemical composition of the pore solution, including the different sulphur-containing ions, was analysed. The precipitation mechanisms during binder hydration in the AAS and OPC systems exhibit significant differences: in AAS the formation of the ‘outer product’ C-S-H is much faster than in OPC. The high Si concentrations in the pore solution during the early hydration of AAS are related to the fast dissolution of Na-metasilicate. The fast reaction of Na is an important factor for the voluminous precipitation of C-S-H within the interstitial space alread...

Polycarboxylate superplasticiser admixtures: effect on hydration, microstructure and rheological behaviour in cement pastes

Abstract: A study was conducted on the effect of a polycarboxylate (PC) admixture on the mechanical, mineralogical, microstructural and rheological behaviour of Portland cement pastes. It was observed that the presence of PC admixture retards the initial cement hydration reactions, although this effect may be offset by possible increased diffusion in later stages. Additionally, the PC admixtures produce a few alterations in the structure and composition of the formed C—S—H gel. The addition of 1% PC admixture in the pastes generates a higher percentage of silicate bridge (Si Q2 units) mainly at 2 days. The admixture used in this study induced microstructural modifications in the pastes which slightly reduced the porosity; however the admixture did not affect the mechanical strength of the pastes at either 2 or 28 days of hydration. Finally, from the results of the rheological studies it was concluded that a low dosage of PC led to a substantial reduction (over 70%) in the yield stress.

Effect of activator mix on the hydration and strength behaviour of alkali-activated slag cements

Abstract: This paper examines on the setting time and mechanical strength behaviour of slag cement pastes activated with different alkaline activators. For this purpose three alkaline solutions were used: waterglass solution (27% SiO2, 18 % Na2O and 55% H2O), NaOH and Na2CO3, maintaining always a constant concentration of Na2O (4% by mass of slag). The solutions were prepared with mixes of 0%, 80%/20% and 20%/80%. The activation process was studied at early ages by conduction calorimetric and fourier transform infrared spectroscopy (FTIR). Results show that the initial pH of the alkaline solution plays an important role in the initial slag dissolution. However the factor playing a decisive role in the acceleration or delay of setting times and in the development of mechanical strengths is the nature of the anion present in the solution. SiO4 2− ions act as an accelerator of the setting time, but CO3 2− ions delay the setting time.