This research used waste ceramic powder (CP) to replace aggregate, fly ash (FA) as filler, and combined them with sulfur to prepare composite cementitious materials. The variations of the mechanical properties with the aggregate proportions (aggregate mass/total mass) of 65%, 70%, and 75%, and the FA contents (FA mass/aggregate and filler mass) of 0%, 10%, 20%, 30%, 40%, and 50% were studied. The correlation evaluation model of sulfur content, CP content, FA content, and mechanical properties was established using the gray correlation theory, and the comprehensive mechanical property evaluation model was established as the foundation of the entropy method. Finally, the optimum proportion of the solid-waste–sulfur-based cementitious composites was determined. Results showed that, without FA, the CP increased from 65% to 75% and the comprehensive mechanical properties of the specimen increased by 60.53%. After FA was added, the peak point of the comprehensive mechanical properties appeared in group S75F10, which was 0.9210. During the hardening of the cementitious material, sulfur was mainly used as a binder, CP played the role of skeleton and part of the filler, whereas, as a crystal nucleus, the FA promoted the transformation of the sulfur crystals. Both the CP and FA can reduce the porosity of the specimen to a certain extent and have potential defect repair ability, thus densifying the matrix and improving the strength. When the proportion of sulfur: CP: FA is 1:2.7:0.3, the flexural (FS), compressive (CS), and splitting tensile (STS) strengths of the specimen are 14.8, 86.2, and 6.8 MPa, respectively. The flexural (FCR) and tensile (TCR) compression ratios are 0.172 and 0.079, respectively.

There are various forms of damage caused by the insufficient shear stress of the bonding coat, if not handled properly, it will lead to serious early damage of the pavement structure. In order to improve the shear resistance of traditional bonding coat, a new pavement method for steel deck is proposed. According to the different particle size and content of crushed stone, 9 kinds of mix proportion were designed. The shear failure form of specimen with different mix proportion is analyzed. Based on the Popovics constitutive model and the piecewise simplified model, the Shear stress-Shear slip (τ-δ) curve of the specimen is described. In addition, a damage model based on interface shear stress and interface shear rigidity is proposed. Finally, based on the engineering case of Mafang bridge in Guangdong province, the effectiveness and potential value of the pavement method are verified.

Calcium silicate slag (CSS) is waste slag and it contains a large amount of beta-dicalcium silicate. This study is mainly focused on the effect of CSS on the hydration of cementitious pastes. CSS was used to partly replace cement, and composite pastes containing CSS and cement were prepared. The mineral composition and particle size distribution of CSS were characterized. The chemically combined water of the paste sample was measured at a given test age. Based on the value of chemically combined water, the hydration degree and the hydration rate of composite pastes were analyzed. The flexural strength of the samples was established. The pore structure and micromorphology of the sample were also observed. The results indicate the chemically combined water decreased, the hydration degree decreased, the hydration rate declined, and the spherical micromorphology of the calcium silicate hydrate gel was reduced after more cement was replaced by CSS in the composite pastes. Besides, the amount of pores increased, its size was bigger, and air content in the pore was higher. However, flexural strength was lower. CSS has a significant impact on the hydration of cementitious pastes, and it is thus suitable to regulate hydration.

The paper aims to investigate the mechanical properties and microstructure of sulfur polymer composite (SPC) containing basalt fiber (BF). The compressive strength f_c, splitting tensile strength f_t, and flexural strength f_f of SPC were tested at different BF contents of 0–3% and aspect ratios of 353 and 706. Meanwhile, the microstructure characteristics of SPC, i.e., the interfacial transition zone (ITZ) structure of SPC, bonding of BF with SPC, pore size distribution, and porosity, were analyzed. The results indicated that the inclusion of BF lowed the compressive strength of SPC; for SPC at a given BF content, the f_c with 706 l/d was lower than that with 353 l/d. Meanwhile, the f_t and f_f of SPC with 353 l/d increased with BF content; for l/d of 706, the f_t and f_f increased with BF content before 2.5% then decreased with the increase in BF content; compared to 353 l/d, 706 l/d was more effective to improve the f_t and f_f of SPC. Additionally, an appropriate amount of BF was beneficial to improve the ITZ structure of SPC and bonding performance between BF and the matrix, and the porosity and pore size of SPC increased with BF content and l/d.

The concrete in the transition strips of expansion joints can become damaged prematurely during the service period. Polyvinyl alcohol (PVA) fiber-reinforced engineered cementitious composite (ECC) is a kind of high ductility concrete material, and its ultimate uniaxial tensile strain is more than 3%. It can be used to improve the damage status of expansion joints. Based on previous research results, ECCs were used in the pilot project of bridge expansion joints. Under this engineering background, the shear load-displacement curves of ECC expansion joints were studied through 27 groups of compression-shear tests of ECC/steel composite structures. The shear failure characteristics of ECC expansion joints were analyzed by the digital image correlation method. A shear load-displacement curve model of the composite structures was proposed based on the equivalent strain assumption and Weibull distribution theory. The results show that the failure mode of the composite structure specimens was ECC shear cracking. Stress and strain field nephograms were used to explain the failure characteristics of the composite structure specimens. The calculated curves of the shear load-displacement model of the composite structures were in good agreement with the experimental curves. The work is of great importance to the shear design of ECC expansion joints and their further engineering applications.

Cement-based material is brittle and is easily damaged by an impact load with a few blows. The purpose of this paper is to study the relations between the impact resistance and tensile properties of cement-based materials reinforced by polyvinyl alcohol fiber (PVA-FRCM). A drop-weight test and uniaxial tension test were performed. The relations were studied based on the experimental results, including the relation between the blow number and the tensile stress at the first visible cracking (σ_c) and the relation between the blow number and the tensile strain at the ultimate failure (ε_f). Results showed that the blow number for the first visible crack for disc impact specimens increases obviously with the increase of σ_c of slab specimens. The crater diameter and blow number for ultimate failure of the disc specimens increase with the increase of ε_f of slab specimens. For the PVA-FRCM specimens with larger σ_c and ε_f, much more blows are needed to cause both the first visible crack and ultimate failure. Polyvinyl alcohol fibers can reinforce impact resistance and tensile properties of cement-based materials.