Supplementary cementitious materials (SCMs) are usually employed to replace partial cement and the pore-solution chemistry of blended cements is extremely essential for their cement hydration and durability. In this work, the pore-solutions of cement pastes with various water-to-cement (w/c) ratios and SCMs (fly ash, ground granulated blast-furnace slag and silica fume) are extracted for observing their ions and conductivities. The results illustrate that Na⁺, K⁺, OH⁻, Ca²⁺ and SO₄²⁻ are the main and their concentrations are declined by the improving w/c ratios and SCMs dosages and thus decreasing their conductivities. The conductivity evolution shows three typical periods: induction (7d). The pore-solution conductivities of pastes with various w/c ratios are predicted well by the model established (R² > 0.90) while the SCMs decline the model effectiveness. The OH⁻, K⁺ and SO₄²⁻ provide the conductivities over 90% of the whole with the contributions in decreasing order.

To solve the problem of state evaluations of small- and medium-span bridges such as concrete continuous girder bridges, this paper developed an extended model based on game theory. Aiming at Nash equilibrium, the combined weighting–fuzzy hierarchical comprehensive evaluation model was constructed by the combination of the analytic hierarchy process and the entropy weight method, which was corrected using the BP neural network. A three-span prestressed concrete continuous girder bridge in Wuhan was evaluated using health monitoring data and manual inspection information and compared to the results obtained using the traditional methods. The evaluation results showed that the error between the first-order frequency and the measured frequency was reduced from 17.95% to 9.00% and the bridge’s overall state score was 89.72. The evaluation model constructed by the method in this paper can take into account the contents of health monitoring and manual detection and coordinate the subjective and objective weights. Compared to the results of the analytic hierarchy process model and the fuzzy comprehensive evaluation model, the proposed model is reliable and applicable.

1. Pervious concrete represents an ecologically sustainable building material, intricately linked to environmental challenges arising from global urbanisation (Chen & Gao, 2020; Liu et al., 2019; L...

Granite sawdust is a by-product in the process of stone processing, which is usually piled up, thus easily causing environmental pollution. To achieve resource utilization, granite sawdust was used as a partial substitution of cement in this work. The effects of different sawdust contents (10–50%) were systematically studied on the pore structure and the mechanical properties of its dry powder mortar. Combined with the grey correlation theory, the correlation between pore size distribution and compressive strength was analyzed. The results showed that the consistency and mechanical properties of the mortar gradually decreased along with the increasing sawdust content, while its critical pore-diameter decreased. The mortar performance was the best when its sawdust content is 10%, which meets the M25 technical requirements. When content reaches up to 30%, the mortar still met the strength standard of M20. Compared to fly ash, the mortar with 30% sawdust as the substitution has a higher water retention rate but lower mechanical strength. The grey correlation analysis indicated that the pores with diameters less than 10 nm and greater than 1000 nm had the most significant impact on the compressive strength.