Effect of chloride and magnesium ions in seawater on the early dissolution of the major clinker in cement (i.e., tricalcium silicate, C₃S) was investigated. The dissolution rates of tricalcium silicate in solutions containing chloride and/or magnesium ions at various concentrations were obtained through lab-made platform and inductively coupled plasma-optical emission spectroscopy. The influence of chloride and magnesium ions on the dissolution heat release of tricalcium silicate was investigated by isothermal calorimetry. The morphology of tricalcium silicate tablet during the dissolution process was determined by scanning electron microscopy. The results show that, chloride ion and magnesium ions both inhibit the dissolution of tricalcium silicate and the inhibiting effect of magnesium ion is more pronounced at a low ionic strength. Sodium chloride and magnesium chloride promote the dissolution of tricalcium silicate at a high ionic strength. The intense solvation of vast sodium and magnesium ions weakens the solvation effect of chloride ion in tricalcium silicate crystal and reduces the stability of water molecules in the solvation shell of chloride ion. Moreover, the presence of massive background ions accelerates the migration of water molecules in the vicinity of the crystal surface, thus promoting the dissolution of chloride ion.

1H-perimidine (PED) and 2-hydroxy-1H-perimidine (HPED) were prepared as corrosion inhibitors for HRB400 reinforced steel in simulated concrete pore solution. The corrosion inhibition performance and adsorption mechanism were investigated via dry and wet cycle experiments, scanning electron microscopy, electrochemical impedance spectroscopy and related theoretical calculations. The results show that the inhibition efficiencies of these compounds are more than 80% for HRB400 reinforced steel in SCP at a concentration of less than 0.12 mmol/L. Moreover, HPED functions as a more effective inhibitor rather than PED due to the presence of 2-position hydroxyl-group. In addition, the inhibitor molecules spontaneously adsorb onto reinforced steel surfaces to form a protective film, and the adsorption process follows the Langmuir isothermal model.

To activate the early-age hydraulic reactivity of steel slag powder (SS), a method of using glacial acetic acid (GA)-anhydrous alcohol solution to modify the SS via dry chemical modification technology was proposed. The mineral composition, surface morphology and specific surface area of unmodified SS and GA modified SS were investigated by X-ray diffraction, Fourier transform infrared, scanning electron microscopy and Brunauer-Emmett-Teller specific surface area analysis. The hydraulic reactivity, compressive strength and soundness of SS pastes and SS blended cement pastes were investigated. The results show that calcite, portlandite and dicalcium ferrite in SS react with GA to produce calcium acetate after GA modification and some pores in the modified process, thus leading to GA modified SS with the greater specific surface area and rougher surface, compared to unmodified SS. In the hydration process, water is easier to absorb onto the surface of modified SS and enters the inner of SS particles along the pores, resulting in higher dissolution heat and reaction heat of active minerals in SS. The result show that, the higher 72-h cumulative hydration heat, the 3 d, 7 d and 90 d compressive strengths and better soundness of GA modified SS pastes and GA modified SS blended cement pastes are obtained, compared to the unmodified pastes.

In order to describe and reconstruct the true irregular particle morphology of cement particles and clarify the hydration process, microstructure evolution and mechanical property development of cement-based materials, an irregular particle reconstruction method was proposed by a discrete method and a central growth model based on a cellular automata theory. A cement particle shape data-base was established. The irregular cement particles were introduced into the CEMHYD3D model, and an irregular basis hydration model was constructed. The effect of particle shape on the hydration process and pore characteristic parameters were analyzed. The reliability and accuracy of the hydration model after the introduction of irregular cement particles were verified. The total porosity and pore size range of the non-spherical-based model are smaller than those of the spherical-based model, while the specific surface area with various pores of the non-spherical-based model is greater than that of the spherical-base model.

Effects of cellulose fiber (CF) and modified cellulose fiber on the mechanical properties, energy evolution, crack propagation and interface failure of cement under dynamic load were investigated by splitting hopkinson pressure bar and high speed-high resolution camera technology. In the third period, the accumulation of specific energy will directly affect the compressive strength of the sample, and the sample with unmodified cellulose fiber (UCF) absorbs more energy and has better compressive strength than the sample with modified cellulose fiber (MCF) at the same fiber incorporation amount. Low-temperature plasma modification can introduce oxygen-containing groups on the surface of cellulose fiber, so that the interface between MCF and cement matrix is more closely bound. The result of this failure is since the modified cellulose fiber-oil well cement composite (MCF-OWC) has a lower compressive strength under dynamic load and a lower crushing degree after failure.

It is of great significance for the optimization and performance improvement of aggregates to investigate the influence of aggregate chemical properties on the nucleation and growth of calcium silicate hydrate (C-S-H) and its mechanism. In this work, limestone, quartz and magnesite were used as aggregates. The interactions between different aggregates and ions in a simulated solution were determined via zeta potential measurement. Also, the nucleation and growth of C-S-H on the surface of these aggregates were analyzed by scanning electron microscopy. The hydration heat of cement pastes with the micro-aggregates was examined to investigate the effect of aggregate chemical properties on the early hydration of cement. The results show that limestone surface has a strong adsorption of Ca²⁺ (i.e., chemical adsorption), leading to a high density of C-S-H nuclei and directional growth of C-S-H, and thus greatly promoting the hydration of cement. The adsorption of Ca²⁺ on quartz surface is due to electrostatic force, which is weaker than that due to the chemical adsorption. The density of C-S-H nuclei on quartz surface is thus much lower than that on limestone surface. In the case of magnesite, its surface has a high affinity for SO₄^2- rather than Ca²⁺, reducing the nucleation density of C-S-H on the surface of magnesite, and thus slowing down the early hydration of cement.

It is well known that mass concrete has the characteristics of huge volume, large amount of raw materials, complex structure and great heat hydration. The temperature cracks occur, thus reducing the performance, safety bearing capacity, durability and service life of the concrete. Hydration heat controlling materials, which can lower the internal temperature rising and temperature stress of the mass concrete, are widely used to reduce the risk of temperature cracks. The effect of hydration heat controlling material type on the hydration heat and the working mechanism was summarized, and the application and future development were discussed, thus providing a design basis for the development of hydration heat controlling materials.

Microbial corrosion of concrete (MICC) is still a problem in concrete engineering. The H₂S and some sulfur compounds in the sewer pipe are oxidized by sulfur oxidizing bacteria to produce biological sulfuric acid, which reacts with the calcium-rich phase in concrete to form gypsum and expansive ettringite and decomposes hydrated calcium silicate formation of insoluble and non-cemented colloids, thus leading to the deterioration of concrete. This review mainly represented recent research work on MICC aspects, including microbial corrosion mechanism, influencing factors, test methods, evaluation indexes and protection measures of concrete as well.

The anti-glare treatment of high alumina glass was carried out by a chemical etching method in an anti-glare etching solution with n(NH₄HF₂)∶n(KHF₂)∶n(C₆H₈O₇)∶n((NH₄)₂SO₄)∶n(TiO₂)∶n(C₆H₁₄O₆) (in molar ratio) at normal temperature. The influence of etching time on the structure and properties was analyzed via the characterization of surface morphology and optical properties. The results show that optimal etching time is 30 min. The anti-glare liquid can etch micron scale pits on the surface of the sample to form a light trapping structure, which can scatter an incident light in all directions and convert the specular reflection into diffuse reflection. Some of the scattered light can be captured by the light trapping structure again and incident repeatedly, which can achieve the anti-glare purpose and maintain the high-transmittance of high aluminum glass.

As a kind of porous clay mineral material, diatomite has some advantages like rich reserves, low cost, and high specific surface area, which can be used as an excellent carrier of phase change material (PCM). Recent work on high-efficiency diatomite PCM is to improve its latent heat and thermal conductivity. This review represented recent research progress on the specific surface area modification and thermal conductivity enhancement modification of diatomite PCM and analyzed the thermal properties of diatomite with different types and contents of PCMs. In addition, some problems of diatomite PCM application were described, and the future research directions were prospected.