Publications

Autogeneous deformation of slag cement concretes under free condition at early age

The Urban Concrete Innovation - Final Draft for Stakeholder Review

The relation between serum biochemistry index and 4 parameters of PLT in pregnancies with livers injury

Objective To study the relationship between serum biochemistry index and 4 parameters of platelet in pregnancies with livers injury.Methods The serum biochemistry index and 4 parameters of PLT from 28 healthy pregnant women (Group A), 30 pregnancies with simple up\|going ALT (Group B) and 27 pregnant patients with jaundice and up\|going ALT(Group C) were analysed and compared.Results ALT, AST, DB, TBA and GGT of group B was higher than that of group A (P0.01). Both TB and Mpv were higher than that in group A (P0.05). But PCT and PLT were lower than that in group A(P0.05). ALT, AST, TB, DB, TBA and ALP of group C was higher than that of group B (P0.01). MPV of group C was higher than that of group B (P0.05), but PCT and PLT of group C was lower than that of group B (P0.05). All the biochemistry index of pregnancies with livers injury and 4 parameters of PLT had been analysed correlately. The positive correlations between MPV and ALT, MPV and AST(or GGT)(P0.05), were found after relative analysis. On contrary, there were the negative correlations between PLT and TB, PLT and DB(P,p.01), PCT and TB, PCT and DB(P0.05).Conclusions Maybe GGT and AlT were not sensitive indices to diagnose jaundice liver injury of the pregnant patients. The amount of PLT of the pregnant patients with livers injury caused by jaundice had been decreased.

New insights into long-term chloride transport in unsaturated cementitious materials: Role of degree of water saturation

Fractal and multifractal analysis on pore structure in cement paste

Mechanisms of autogenous shrinkage of alkali-activated slag and fly ash pastes

This study aims to provide a better understanding of the autogenous shrinkage of slag and fly ash-based alkali-activated materials (AAMs) cured at ambient temperature. The main reaction products in AAMs pastes are C-A-S-H type gel and the reaction rate decreases when slag is partially replaced by fly ash. Due to the chemical shrinkage and the fine pore structure of AAMs pastes, drastic drop of internal relative humidity is observed and large pore pressure is generated. The pore pressure induces not only elastic deformation but also a large creep of the paste. Besides the pore pressure, other driving forces, like the reduction of steric-hydration force due to the consumption of ions, also cause a certain amount of shrinkage, especially in the acceleration period. Based on the mechanisms revealed, a computational model is proposed to estimate the autogenous shrinkage of AAMs. The calculated autogenous shrinkage matches well with the measured results.

Prediction & optimization of alkali-activated concrete based on the random forest machine learning algorithm

Microstructural analysis of cement paste: experimental and numerical investigation

This work was financially supported by project POCI-01-0145-FEDER-007457 – (CONSTRUCT - Institute of R&D in Structures and Construction) and by project POCI-01-0145-FEDER-007633 (ISISE) funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) – and by national funds through FCT - Fundacao para a Ciencia e a Tecnologia. FCT and FEDER (COMPETE2020) are acknowledged for the funding of the research project PTDC/ECM-EST/1056/2014 (POCI-01-0145-FEDER-016841). The first author also thanks the individual grant with reference number of SFRH/BPD/114754/2016 funded by FCT.

Numerical simulation of interfacial transition zone in ternary blended cement based composites

A Lattice Boltzmann single component model for simulation of the autogenous self-healing caused by further hydration in cementitious material at mesoscale

Effect of Mineral Admixture on Mechanical Properties of Concrete by Adjusting Interfacial Transition Zone Microstructure

Modelling microstructural changes of ordinary Portland cement paste at elevated temperature

On the material level, the deterioration of ordinary Portland cement (OPC) paste at elevated temperature is attributed to chemical transitions and microstructural cracking. However, few studies on the quantitative characterisation of the degradation process of OPC paste have been reported and thus the quantitative relationship between microcracking and strength loss of OPC paste remains unclear. A simulation procedure for modelling the microstructural changes of OPC paste at elevated temperature was developed in this work. After the microstructural simulation, a virtual tensile test was performed on fire-damaged microstructures in order to evaluate the tensile strength and Young's modulus. The strength losses of OPC paste due to both chemical transitions and microcracking were then quantified.

Modeling of ionic diffusivity in non-saturated cement-based materials using lattice Boltzmann method

A novel lattice model to predict chloride diffusion coefficient of unsaturated cementitious materials based on multi-typed pore structure characteristics

Electroless Ni-B Alloy Plating from DMF at Room Temperature

A new basic solution for eletroless Ni-B alloy plating from DMF was studied. The effects of composition and operating conditions on the rate of deposition of Ni-B alloy have also been discussed. The alloy component was analyzed by EDS and Inductively Coupled Plasma (ICP). The plating rate is determined by electronic balance. And structures of the plating coatings were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD).The optimum composition and operating conditions for abstaining satisfied Ni-B alloy coating are provided.

Pre-Treatments Of Mswi Bottom Ash For The Application As Supplementary Cememtitious Matreial In Blended Cement Paste

At present, most municipal solid waste incineration (MSWI) bottom ash, as being disposed of as waste, is directly landfilled, raising concern about the environmental issue and potential loss of resources. Given that the natural raw materials used for cement production are being depleted, the recycling of MSWI bottom ash for the application as building materials is meaningful and promising. The feasibility of using MSWI bottom ash as mineral additives in concrete has been demonstrated in the literature. In this research, as-received MSWI bottom ash has high mineral content and shows stable leaching behaviour. But, when used as cement substitute, the residual metallic Al in bottom ash always causes matrix swelling and strength loss by reacting with Ca(OH)2 and releasing H2 gas. In this research, dry and wet pretreatment methods were performed to remove the metallic Al in as-received bottom ash (0- 2mm). The results show that both of these two methods are effective. When comparing these two methods, wet method is time-consuming but can remove the metallic Al completely; dry method is fast but always has limitation that it can only reduce the metallic Al content by 80%. Regarding compressive strength, the decrease introduced by 10% dry-treated bottom replacement in cement paste is less than that of wet-treated bottom ash. The lower strength development observed in wet-treated bottom ash blended cement may be due to the removal of soluble reactive phases during the treatment.

Apparent Activation Energy of Cement Blended with Rice Husk Ash

The hydration kinetics of cement depends on the reaction temperature. An issue related to the effects of curing temperature on cement hydration is the apparent activation energy (Ea). The effect of Rice husk ash (RHA) on Ea is still not clear. This paper studies the Ea of Portland cement blended with RHA using isothermal calorimetry. Based on the experimental data, the Ea of RHA blended cement was first calculated with the hydration process. Besides, the mean Ea was also calculated according to the modified ASTM C 1074 method. In this study, it was observed that the Ea depends on the degree of hydration, water to binder ratio, temperature, and the RHA replacement. The variation of Ea along with the degree of hydration reflects the change in the mechanism during the hydration process.

A conceptual design of two-stream alkali-activated materials