摘要：In order to investigate the influence of three key molar ratios （n（SiO2）/n（Al2O3）, n（K2O）/n（Al2O3） and n（H2O）/n（K2O））, a total of nine potassium poly-sialate-disiloxo （K-PSDS） geopolymeric cement matrices were designed according to orthogonal design principle. Subsequently, XRD, ESEM-EDXA and MAS-NMR techniques were employed to further characterize the microstructure of the most fully reacted geopolymeric cement matrix. The experimental results show that n（K2O）/n（Al2O3） has the most significant effect on compressive strength amongst the three ratios. The highest compressive strength （20.1 MPa） can be achieved when n（SiO2）/n（Al2O3）=6.5, n（K2O）/n（Al2O3）=0.8 and n（HEO）/n（K2O）=10.0. The FTIR spectra of nine PSDS geopolymeric cement matrices also indicate that geopolymeric cement matrix with the highest strength is the most fully reacted one and possesses the largest amount of geopolymeric cement products. The microscopic analysis reveals that PSDS geopolymeric cement matrix possesses structural characteristics similar to gel substances in having a wide range of Si endowments, but predominantly the framework molecular chains of Si partially replaced by 4-coordinated Al tetrahedral.

摘要：To explore the tensile property parameters in the structural design of bridge deck link slabs made by ecological high ductility cementitious composites (Eco-HDCC), the tensile properties of Eco-HDCC exposed to interactive freeze-thaw-carbonation cycles and single carbonation cycles were studied. The carbonation front of Eco-HDCC was determined by X-ray diffraction and differential scanning calorimetry-thermal gravimetric methods. Results indicate that the carbonation front of Eco-HDCC after interaction tests is deeper than that of Eco-HDCC after single carbonation tests. In addition, the ultimate tensile strength for Eco-HDCC shows an increasing trend after the interaction of 1 to 5 cycles compared with that of virgin specimens, while the ultimate tensile strength decreases after the interaction of 10 to 15 cycles. For single carbonation tests, the ultimate tensile strength of Eco-HDCC increases as cycles increase. After being subjected to interaction and single carbonation environments, both the ultimate tensile strain and tensile strain energy of Eco-HDCC decrease as cycles increase, and the decrease degrees of Eco-HDCC after interaction cycles are larger than those of Eco-HDCC after single carbonation. For general consideration, the tensile stress-strain relationship of Eco-HDCC after the interaction of 15 cycles can be adopted in the design of bridge deck link slabs for the purpose of safety.

摘要：To obtain the design parameters of the structure made by ecological high ductility cementitious composites(Eco-HDCC),the effects of curing age on the compressive and tensile stress-strain relationships were *** reaction degree of fly ash,non-evaporable water content and the pH value in pore solution were calculated to reveal the mechanical *** results indicate that as the curing age increases,the peak compressive strength,peak compressive strain and ultimate tensile strength of Eco-HDCC ***,the ultimate compressive strain and ultimate tensile strain of Eco-HDCC decrease with the increase in curing ***,as the curing age increases,the reaction degree of fly ash and non-evaporable water content in Eco-HDCC increase,while the pH value in the pore solution of Eco-HDCC ***,the simplified compressive and tensile stress-strain constitutive relationship models of Eco-HDCC with a curing age of 28 d were suggested for the structure design safety.

摘要：In order to establish the constitutive relationship of high-ductility cementitious composites(HDCCs)under uniaxial tensile load and to guide the structural design of HDCCs,based on the analysis of the existing uniaxial tensile constitutive relationship and ideal elastoplastic linear strain-hardening model,a bilinear tensile constitutive equation of HDCCs was *** points of nominal initial cracking and nominal maximum stress were adopted as control points of the line segment,and the constitutive relationship of HDCCs was *** series of uniaxial tensile stress-strain curves of HDCCs were combined to perform an experimental application of the constitutive equation,along with an analysis of the key *** experimental results confirm the ability of the constitutive equation to overcome the problem of insufficient or excessive redundancy of existing models in terms of calculation bearing ***,the measured maximum stress value is larger than the nominal value,and the ratio between the two values ranges from 1.08 to ***,the tensile strain at the softening point obtained by fitting a straight line with the valley points of the strain-hardening stage curve is greater than or equal to the tensile strain at the measured maximum stress point and the ratio of the fitted values to the measured values ranges from 1.00 to 1.19.