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 ...

The mechanical behavior of multicracks under compression has become a very important project in the field of fracture mechanics and rock mechanics. In this paper, experimental and numerical studies on the fracture property of three collinear cracks under compression were implemented. The specimens were a square concrete plate, and the cracks were made by a very thin film. The tests were conduct...

Previous research has demonstrated a linear relationship between compressive strength (mortar cubes and concrete cylinders) and cumulative heat release normalized per unit volume of (mixing) water for a wide variety of cement-based mixtures at ages of 1 d and beyond. This paper utilizes concurrent ultrasonic reflection and calorimetry measurements to further explore this relationship from the t...

The objective of this study is to examine the effect of substitution of cement by three different mineral additions, on the mortar rheological and mechanical properties. This experimentation, considers the fineness of mineral additives with a constant workability. Ordinary Portland Cement was partially replaced by different percentages of slag, pozzolana and metakaolin of 10, 20 and 30%. The ob...