The hydration and pore structure of sulphoaluminate MDF cement were studied by X-ray diffractometer (XRD),scanning electron microscope(SEM) and mercury intrusion porosimeter(MIP) etc.The experimental results indicate ...The hydration and pore structure of sulphoaluminate MDF cement were studied by X-ray diffractometer (XRD),scanning electron microscope(SEM) and mercury intrusion porosimeter(MIP) etc.The experimental results indicate that hydration products of the materials are entringites(AFt),aluminium hydroxide and CSH (I) gel etc.Due to its very low water-cement ratio,hydration function is only confined to the surfaces of cement grains,and there is a lot of sulphoaluminate cement in the hardenite which is unhydrated yet.Hydration reaction was rapidly carried under the condition of the heat-pressing.Therefore cement hydrates AFt,CSH (I) and aluminium hydroxide gel fill in pores.The expansibility of AFt makes the porosity of MDF cement lower (less than 1 percent) and the size of pore smaller (80 percent pore was less than 250?),and enhances its strength.展开更多
The method of examining micro-pores in su lp hoaluminate MDF cement by means of the Positron Annihilation Technique (PAT) was discussed.The results show that the intensity I 2 of positrons annihilation wi th moderat...The method of examining micro-pores in su lp hoaluminate MDF cement by means of the Positron Annihilation Technique (PAT) was discussed.The results show that the intensity I 2 of positrons annihilation wi th moderate life-span (τ 2≈330Ps) increases regularly with the addition of t he numbers of micro-pores (less than 250?). Therefore, the value of I 2 may b e used to opitomize the compactness and integrity of the MDF cement structure. A t the same time, the experiment result of PAT was compared with that of Mercury Intrusion Porosimeter (MIP).展开更多
The enhancement of interface bonding between cement and polymerand the structural reticula-tion of the water-soluble polymer areproposed to minimize the shortening of the mechanical properties ofmacro-de-fect-free(MDF...The enhancement of interface bonding between cement and polymerand the structural reticula-tion of the water-soluble polymer areproposed to minimize the shortening of the mechanical properties ofmacro-de-fect-free(MDF)cement based composites at high relativehumidity.The MDF composites incorporated with vari-ouscross-coupling agents studied experimentally.The results show thatthe MDF composites modified with small amounts of cross-couplingagent had raised mechanical properties,but it is more important thatthe modified MDF composites had a significant increase in waterresistance compared to the original one.展开更多
MDF cement material,a new kind of high strength polymer cement,has an exellent property of bending strength. It is supposed that this property attributes to the mechanism of improving interface strength. In this paper...MDF cement material,a new kind of high strength polymer cement,has an exellent property of bending strength. It is supposed that this property attributes to the mechanism of improving interface strength. In this paper, the bonding behaviours on the composite interface between polyacrylamide and aluninous cement are studied with microimage, XPS surface analysis technique and fracture surface analysis. Actions on the improving interface in this material are discussed.展开更多
文摘The hydration and pore structure of sulphoaluminate MDF cement were studied by X-ray diffractometer (XRD),scanning electron microscope(SEM) and mercury intrusion porosimeter(MIP) etc.The experimental results indicate that hydration products of the materials are entringites(AFt),aluminium hydroxide and CSH (I) gel etc.Due to its very low water-cement ratio,hydration function is only confined to the surfaces of cement grains,and there is a lot of sulphoaluminate cement in the hardenite which is unhydrated yet.Hydration reaction was rapidly carried under the condition of the heat-pressing.Therefore cement hydrates AFt,CSH (I) and aluminium hydroxide gel fill in pores.The expansibility of AFt makes the porosity of MDF cement lower (less than 1 percent) and the size of pore smaller (80 percent pore was less than 250?),and enhances its strength.
基金Funded by the"863"High tech Program(No.2002AA335050)
文摘The method of examining micro-pores in su lp hoaluminate MDF cement by means of the Positron Annihilation Technique (PAT) was discussed.The results show that the intensity I 2 of positrons annihilation wi th moderate life-span (τ 2≈330Ps) increases regularly with the addition of t he numbers of micro-pores (less than 250?). Therefore, the value of I 2 may b e used to opitomize the compactness and integrity of the MDF cement structure. A t the same time, the experiment result of PAT was compared with that of Mercury Intrusion Porosimeter (MIP).
文摘The enhancement of interface bonding between cement and polymerand the structural reticula-tion of the water-soluble polymer areproposed to minimize the shortening of the mechanical properties ofmacro-de-fect-free(MDF)cement based composites at high relativehumidity.The MDF composites incorporated with vari-ouscross-coupling agents studied experimentally.The results show thatthe MDF composites modified with small amounts of cross-couplingagent had raised mechanical properties,but it is more important thatthe modified MDF composites had a significant increase in waterresistance compared to the original one.
文摘MDF cement material,a new kind of high strength polymer cement,has an exellent property of bending strength. It is supposed that this property attributes to the mechanism of improving interface strength. In this paper, the bonding behaviours on the composite interface between polyacrylamide and aluninous cement are studied with microimage, XPS surface analysis technique and fracture surface analysis. Actions on the improving interface in this material are discussed.
