Assessment of self-healing behavior of polypropylene fiber-reinforced cement mortar with crystalline admixture: the effects of crack widths, cracking ages, and external conditions

Crystalline admixture (CA) is an effective self-healing agent for mortar. However, the effects of crack parameters (i.e. crack width and cracking age) and the service environment on the self-healing behavior of CA-containing mortar are not well understood. Herein, the self-healing behavior of mortar containing a self-developed CA was assessed...

Effects of temperature on autogenous deformation and early-age stress evolution in cement pastes with low water to cement ratio

This paper investigates the influence of temperature on autogenous deformation and early-age stress (EAS) evolution in ordinary Portland cement paste using a recently developed Mini Temperature Stress Testing Machine (Mini-TSTM) and Mini Autogenous Deformation Testing Machine (Mini-ADTM). In the Mini-TSTM/ ADTM, CEM I 42.5 N paste with a...

Behavior of Engineered Cementitious Composites (ECCs) Subjected to Coupled Sustained Flexural Load and Salt Frost

The performance of engineered cementitious composites (ECCs) under coupled salt freezing and loaded conditions is important for its application on the transportation infrastructure. However, in most of the studies, the specimens were generally loaded prior to the freezing. The influence of sustained load was merely considered. To this end,...

Numerical study of interactive ingress of calcium leaching, chloride transport and multi-ions coupling in concrete

In circumstances with wastewater and seawater, the behavior of multi-ions including calcium, chloride and others in concrete attracts attention. The present study investigated the multiple mechanisms that could happen under the special field situation above, including calcium leaching, chloride transport and multi-ion coupling. To realize the...

Influence of coarse aggregate settlement induced by vibration on long-term chloride transport in concrete: a numerical study

High-frequency vibration helps to improve the compactness of concrete, but also causes the settlement of coarse aggregates (CAs) and then affects the durability of hardened concrete. In this paper, a numerical study combining multi-phase CA settlement model and multi-component ionic transport model is performed to understand the influence of...

Numerical investigation of external sulfate attack and its effect on chloride binding and diffusion in concrete

Reinforced concrete (RC) structures may suffer from serious durability problems during long-term service. To investigate the deterioration of RC structures subjected to the dual attacks of chlorides and sulfates, this study proposes a coupled model for external sulfate attack (ESA) and its effect on chloride binding and diffusion. To account for...

Modelling and Simulation for Concrete Durability: Mechanism and Prediction

An experimental and numerical investigation of coarse aggregate settlement in fresh concrete under vibration

Fresh concrete needs vibration to compact, fill the mould and reach a dense state. During the compaction process, coarse aggregates (CAs) tend to settle, affecting the homogeneity and eventually the long-term durability of hardened concrete. In this study, a 3-D, multi-phase numerical model for fresh concrete is developed for better...

Influence of SiO₂, TiO₂ and Fe₂O₃ nanoparticles on the properties of fly ash blended cement mortars

This study explores the effects of different types of nanoparticles, namely nano-SiO₂ (NS), nano-TiO₂ (NT), and nano-Fe₂O₃ (NF) on the fresh properties, mechanical properties, and microstructure of cement mortar containing fly ash as a supplementary cementitious material. These nanoparticles existed...

Modelling of deformation and fracture for a model quasi-brittle material with controlled porosity: Synthetic versus real microstructure

Deformation and fracture of materials are usually considered in terms of brittle and ductile modes. However, there is an intermediate class between these limits that is termed quasi-brittle where there is measurable inelastic deformation prior to final graceful ‘brittle’ failure. In previous work, we presented deformation and fracture data...

Towards understanding the influence of porosity on mechanical and fracture behaviour of quasi-brittle materials: Experiments and modelling

In this work, porosity-property relationships of quasi-brittle materials are explored through a combined experimental and numerical approach. In the experimental part, hemihyrate gypsum plaster powder (CaSO 4 ⋅1/2H 2 O CaSO4⋅1/2H2O) and expanded spherical polystyrene beads (1.5–2.0 mm dia.) have been mixed to form a model material with...

An experimental and modelling evaluation of the deformation and fracture of quasi-brittle reticulated vitreous carbon foam

In quasibrittle materials the addition of specific microstructural features such as porosity can lead to departure from linear elastic behaviour prior to maximum force, followed by graceful failure. A simple but extreme example is reticulated vitreous carbon foam, with its opencell structure of brittle ligaments connected in a threedimensional...