this paper aims at investigating the influence of partial replacement of portland cement with ultrafine fillers compared to limestone powder on the durability and mechanical characteristics of concrete. for this purpose, ultrafine calcium carbonate materials with different specific surface areas of 9.7 and 15.1 m2/g and limestone powder (0.72 m2/g) were used. the results indicate that the ultra...

Applications of acoustic emission (AE) to structural integrity of concrete are summarized, dealing with both fresh and hardened concrete. Under mixing concrete, AE activity is applied to estimate the consistency. After hardened, in a uniaxial compression test, AE activity is modeled by the rate process theory and is correlated with the damage degree. For inspection of reinforced concrete (RC) m...

Multiscale modeling for cement-based materials, such as concrete, is a relatively young subject, but there are already a number of different approaches to study different aspects of these classical materials. In this paper, the parameter-passing multiscale modeling scheme is established and applied to address the multiscale modeling problem for the integrated system of cement paste, mortar, and...

The available literature identifies that the addition of mineral admixture as partial replacement of cement improves the microstructure of the concrete (i.e., porosity and pore size distribution) as well as increasing the mechanical characteristics such as drying shrinkage and creep, compressive strength, tensile strength, flexural strength, and modulus of elasticity; however, no single documen...

High strength hydraulic concrete was introduced based on its thermo-dynamic and strain-stress characteristics. The compound exponential thermo-dynamic creep model was established. The temperature rise models were interpreted. The bisection constitutional model was deduced as the approach to express the strain-stress non-linearity of high strength hydraulic concrete. The key parameters on thermo...

High Performance Fiber Reinforced Cementitious Composite (HPFRCC) materials exhibit strain hardening behavior with multiple cracking under tensile loading. In this paper, experimental and parametric studies are performed to assess the influence of using HPFRCC material instead of normal concrete in reinforced concrete beams. After calibrating the experimental results, the analytical results inc...

The disposal of ready mixed concrete truck wash water and returned plastic concrete is a growing concern for the ready mixed concrete industry. Recently, extended set-retarding admixtures, or stabilizers, which slow or stop the hydration of portland cement have been introduced to the market. Treating truck wash-water or returned plastic concrete with stabilizing admixtures delays its setting an...

Using nano-technology materials in the asphalt pavement industry is new compared with Portland cement concrete. The main objective of this study is to investigate the effects of nano-silica modification on some properties of a penetration grade asphalt cement and a typical asphalt concrete. 60/70 penetration grade bitumen was modified with different percentages of nano-silica (i.e. 1, 3 and 5%,...

In recent years, the Lamb wave analysis by the multi-channel analysis of surface waves (MASW) for concrete structures has been an effective nondestructive evaluation, such as the condition assessment and dimension identification by the elastic wave velocities and their reflections from boundaries. This study proposes an effective Lamb wave analysis by the practical application of MASW to concre...

We analyze the concrete security provided by a signature scheme described in a recent Internet Draft by McGrew and Curcio.