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Chloride ions penetrated into reinforced concrete members causes rebar corrosion and induce the volume expansion of the rebar and cracks of concrete cover. This study aims to predict the chloride ingress in the reinforced concrete member and its operational service life by using a lattice model. Concrete is considered at the mesoscale, which constitutes three phases: aggregates, cement matrix and interfacial transition zones (ITZ). Fick’s second law was implemented into the lattice model to describe the diffusion of the chloride ions within concrete. The diffusivity coefficient of aggregates is almost null, whereas those of cement paste and of ITZ is deduced from macroscopic diffusivity measures. Numerical solutions are validated against the test data and the analytical solution. The effect of the aggregate volume fraction is discussed. Curves, which help to determine the service life of the reinforced concrete structure from the cover thickness, is resulted from the lattice modelling for concrete with different aggregate volume fractions.

The stability of the tunnel face during tunneling is one of the major criteria for the design and construction of the tunnel. Collapse and blowout are two modes of tunnel face failure during the excavation. The cover-to-diameter ratio is one of the main parameters controlling these failure modes. Several analytical solutions have been proposed to estimate the range of support pressure applied on the tunnel face to avoid both the collapse and the blowout. However, most of those models deal with homogeneous soils. This paper aims at proposing an analytical model to predict the blowout of the tunneling face of a tunnel in multi-layered soils. The derivation is based on a limit equilibrium analysis, which considers the water tCiable. The proposed model is validated against the real blowout data reported from the tunneling in the Second Heinenoord Tunnel project in the Netherlands. Then, the maximum support pressure exerted on the tunneling face is predicted as a function of the cover-to-diameter ratio, the tunnel diameter, and the water table level for five representative soils. Finally, the model is applied to an underground segment of the Hanoi Metro Line 3 project (in Vietnam) to show the role of the multi-layer aspect.

The need to rebuild and upgrade old structures has grown in recent years, particularly in large urban areas. These renovation and upgrade activities frequently affect the structural load of the building, eventually increasing the loads acting on the foundation. This paper illustrates a case study in which the cement grouting method was used to improve the load-carrying capability of an old structure's foundation. The influence of various key variables of the cement grouting method, such as the diameter, length, and angle of inclination of the mortar pile, was also assessed using the finite element (FE) method, Plaxis 2D. Finally, the optimum parameters for the strengthening method used in the study building were chosen based on the FE analysis results of the improvement of the bearing capacity of the foundation using the cement slurry grouting method.

Ecofriendly, ecoefficient and sustainable civil engineering work has been research with emphasis on adapting the byproducts of solid waste recycling and reuse to achieving infrastructural activities with low or zero carbon emission. The direction combustion model, the solid waste incinerator caustic soda oxides of carbon entrapment model (SWI-NaOH-OCEM) developed by this research has achieved a zero carbon release. This research adopted the literature search method to put together research results of previous works relevant to the aim of this present work. It has been shown that CO and CO2 emissions can be contained during the derivation of alternative or supplementary cementing materials used in the replacement of ordinary Portland cement in civil engineering works. In the overall assessment of the present review work has left the environment free of the hazards of CO and CO2 emissions. It was shown that these supplementary cementing materials derived from solid wastes improve the engineering properties of treated soft clay and expansive soils, concrete, and asphalt. Bio-peels, another form solid waste has been established as a good detoxificant used in treating wastewater. It has been shown that solid waste recycling and reuse is a hub to achieving ecofriendly, ecoefficient and sustainable infrastructural development on the global scale. [ABSTRACT FROM AUTHOR]