Results: The experiment results indicate that the type of recycled aggregate and its replacement ratio have significant effects on the freezethaw performance. The cubic compressive strength of recycled aggregate concrete is overall slightly lower than that of normal concrete. After 100 freeze-thaw cycles, the compressive strength decreases and the reduction extent increases with increasing repl...

OBJECTIVES To assess compressive strength and effect of duration after photoactivation on the compressive strength of different dual cure bulk fill composites. METHODS Seventy-two disc shaped (4x10mm) specimens were prepared from three dual cure bulk fill materials, ZirconCore (ZC) (n=24), MulticCore Flow (MC) (n=24) and Luxacore Dual (LC) (n=24). Half of the specimens in each material were t...

The aim of this research was to study the effect of various water-to-cement ratio on the properties of pervious concrete. Tests were carried out to find the optimum water-to-cement ratio that gives a high compressive strength with acceptable permeability. The tests of fresh density, compressive strength at 7days, porosity and water permeability for four mixes of pervious concrete with various w...

In this chapter, we will present the precursors and manufacturing of carbon fibers. Among the precursors used for the production of carbon fibers, polyacrylonitrile (PAN)-based and pitch-based precursors are the most important. A significant amount of work has been done on relating the fiber structure to the properties and translating that relationship into production for either reducing cost o...

Introduction: In 2001, Cavex presented the first test results, which showed 5 days dimensional stability for Cavex ColorChange. More than 10 years we used this information to show our customers the high quality and stability of our products. In the meantime, our Research & Development department worked on improvements of the alginate impression materials. We formed close cooperation’s with supp...

The type of lightweight aggregate and its volume fraction in a mix determine the density of lightweight concrete. Minimizing the density obviously requires a higher volume fraction, but this usually causes aggregates segregation in a conventional mixing process. This paper proposes a two-stage casting process to produce a lightweight concrete. This process involves placing lightweight aggregate...

This study estimates the strength of concrete, an attempt is also made to increase the accuracy of Calculating the strength, using the nondestructive test (NDT) surface hardness rebound value, material design parameters and regression analysis. The strength of the concrete specimens was 130 480 kgf/cm, and their ages were 7 38 days. In total, 166 standard specimens of concrete were grouped into...

Aquaculture is among the oldest occupations of human being. Over the past quarter of century, the aquaculture industry has grown rapidly. The effect of water containing sodium sulfate on long term compressive strength of concrete of fishing ponds and channels is investigated in this paper. Aim of this paper was to analyze the strength of concrete channels and of aquaculture which are in direct ...

this paper deals with the interfacial effects of silica fume (sf) and styrene-butadiene polymer (sbr) on compressive strength of concrete. analyzing the compressive strength results of 32 concrete mixes performed over two water-binder ratios (0.35, 0.45), four percentages replacement of silica fume (0%, 5%, 7.5%, 10%) and four percentages of sbr (0%, 5%, 10%, 15%) were investigated. a mathemati...

this paper introduces an innovative partially destructive method, called “twist-off”, for the assessment of in situ concrete strength. in this method a 40mm diameter metal probe is bonded to a concrete surface by means of a high strength epoxy resin adhesive. to measure the concrete compressive strength, a torque is applied using an ordinary torque-meter and the maximum shear stress at failure ...