Size effect on compressive strength of foamed concrete: Experimental and numerical studies

This study investigates the size effect on the compressive strength of foamed concrete at the mesoscale level combining X-ray computed tomography (X-CT) and a discrete lattice model. Image segmentation techniques and X-CT were employed to obtain virtual specimens comprising hydrated cement paste and air voids. The lineal-path function and...

Energy consumption of a laboratory jaw crusher during normal and high strength concrete recycling

This paper presents the measurement and analysis of energy consumption of a laboratory jaw crusher during concrete recycling. A method was developed to estimate the power requirements of a lab-scale jaw crusher. The impact of material properties on the crusher performance is studied. Eight concrete strength classes (C20/25–C80/95) were...

Fresh properties of limestone-calcined clay-slag cement pastes

Formulation of quaternary blended system containing ordinary Portland cement or clinker, slag, limestone and calcined clay (LC2) appeared to be a viable approach to developing low-clinker cements without severely sacrificing mechanical performance at later ages. This paper investigates the effect of two material parameters, i.e., LC2-to-slag...

Influence of liquid-binder ratio on the performance of alkali-activated slag mortar with superabsorbent polymer

The influences of liquid-binder ratio and mixing sequence on the performance of superabsorbent polymer (SAP)-containing alkali-activated slag (AAS) mortar are investigated in this study. It is found that the SAP absorbs much less liquid in upper supernatant of AAS than in water. Mixing SAP with liquid first induces a larger absorption...

Report of RILEM TC 267-TRM phase 3: validation of the R³ reactivity test across a wide range of materials

RILEM TC 267 TRM– “Tests for Reactivity of Supplementary Cementitious Materials” recommends the Rapid Reliable Relevant (R3) test as a method for determining the chemical reactivity of supplementary cementitious materials (SCMs) in Portland cement blends. In this paper, the R3 test was applied to 52 materials from a wide range of conventional...

Oil-well lightweight cement slurry for improving compressive strength and hydration rate in low-temperature conditions

Inadequate early compressive strength is a common problem when employing lightweight cement (LWC) slurries during the cementing of oil wells under low-temperature conditions. A new formulation of LWC slurry was investigated by the Research Institute of Petroleum Industry (RIPI) to improve the compressive strength and hydration rate of LWC...

Influence of ambient temperature on the mechanical properties of macro fibre reinforced concrete

The incorporation of macro fibers have been an effective method to improve the mechanical and durability properties of concrete. As the mechanical properties of Macro fiber reinforced concrete are mostly tested at room temperatures, the effect of ambient temperature on the mechanical properties have been rarely reported. In this investigation,...

Influence of carbon dioxide as a mixture component on the cement hydration

Concrete is the most widely material used in the construction industry. However, it has a great environmental impact, mainly because of cement manufacture and the inherent CO2 emissions into the atmosphere. This research intends to contribute to the reduction of the environmental impact of the concrete industry through the uptake of CO2 during...

A multiscale model for predicting the mechanical properties of cement paste

Mechanical properties of cement paste are indispensable and frequent requirement in structural analysis of concrete and other cement-based materials, and therefore the theoretical predictions have obtained considerable attention in the field of material engineering. Despite of being an active research area, available models for accurately...

Effect of different grade levels of calcined clays on fresh and hardened properties of ternary-blended cementitious materials for 3D printing

This study aims to investigate the influences of different grades of calcined clay on 3D printability, compressive strength (7 days), and hydration of limestone and calcined clay-based cementitious materials. Calcined clays that contained various amounts of metakaolin were achieved by blending low-grade calcined clay (LGCC) and high-grade...

Combined experimental and numerical study of uniaxial compression failure of hardened cement paste at micrometre length scale

The aim of this work is to investigate the mechanical performance of hardened cement paste (HCP) under compression at the micrometre length scale. In order to achieve this, both experimental and numerical approaches were applied. In the experimental part, micrometre sized HCP specimens were fabricated and subjected to uniaxial compression by...

RILEM TC 247-DTA round robin test: mix design and reproducibility of compressive strength of alkali-activated concretes

The aim of RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ is to identify and validate methodologies for testing the durability of alkali-activated concretes. To underpin the durability testing work of this committee, five alkali-activated concrete mixes were developed based on blast furnace slag, fly ash, and flash-calcined...

Effect of admixture on the pore structure refinement and enhanced performance of alkali-activated fly ash-slag concrete

This paper investigates the influence of a plasticizing admixture on the pore structure refinement of alkali-activated concrete and paste mixtures and the consequently enhanced performance. Alkali-activated fly ash-slag concrete and paste are designed using a polycarboxylate-based admixture with different dosages. The pore structure and...

CoRncrete: A corn starch based building material

Starch is a natural polymer which is commonly used as a cooking ingredient. The renewability and bio-degradability of starch has made it an interesting material for industrial applications, such as production of bioplastic. This paper introduces the application of corn starch in the production of a novel construction material, named CoRncrete...

Fatigue damage in composites under different loading conditions

The damage development In notched (± 45, 0„, 90, 0-) carbon-epoxy coupon specimens tested under different loading conditions was determined. Constant amplitude tests at R = -1 and R = 0.1 as well as flight simulation tests were performed to establish those stress values for which no damage growth occurs.