This study was conducted to evaluate the effects of inclusion of fly ash on concrete microstructure and its mechanical performance. Air entrained plain portland cement concrete was proportioned to obtain design strength of 6000 psi at the 28-day age. Concrete mixtures were also proportioned to have various cement replacements in the range of 15 70% with an ASTM Class C fly ash. Microstructure o...

In this paper, to study mechanical properties of manufactured-sand concrete after high temperatures, experiments on the residual strength of manufactured-sand concrete were carried out under high temperatures in which raw materials performances and concrete mixture proportion were considered. The mechanism of elevated temperatures on residual strength was theoretically discussed, and the calcul...

The experimental study deals with Hybrid fibre reinforced concrete with the use of (Polypropylene and Recycled polyethylene terephthalate RPET). The M40 grade concrete used was designed by using IS10262-2009 code. The steel fibre and synthetic fibre were added at the volume fractions up to 0.5%. Test results showed that the fibres, when used in a hybrid form, could result in superior composite ...

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...

This study developed a macro-sized polyamide (PA) fiber for concrete reinforcement and investigated the influence of the PA fiber on flexural responses in accordance with ASTM standards. PA fibers are advantageous compared to steel fibers that are corrosive and gravitated. The macro-sized PA fiber significantly improved concrete ductility and toughness. Unlike steel fibers, the PA fibers produc...

Fiber reinforced concretes (FRCs) exhibit property improvement caused by the fibers. By using gamma radiation we have further improved mechanical properties of hydraulic concretes elaborated with Portland cement, water, silica sand, marble and polypropylene (PP) fibers. Compression strength, compression modulus, impact strength and dynamic elastic modulus were determined. Impact fatigue testing...

Recycled concrete aggregate (RCA) collected from the demolition of old reinforced structures can be reused to prepare structural and non-structural concrete, thereby protecting environment by preserving natural resources. This study explores RCA’s use, crushed different building projects in Riyadh, manufacture fresh self-compacting (SCC) investigate its properties hardened state. Four SCC mixes...

We present the results of an experiment examining the extent to which individuals will tolerate delays when told that such delays are for security purposes. In our experiment, we asked 800 Amazon Mechanical Turk users to count the total number of times a certain term was repeated in a multipage document. The task was designed to be conducive to cheating. We assigned subjects to eight between-su...