The performances of cementitious materials as well as the efficiency of construction are adversely affected at high temperatures. Previous studies have already demonstrated that ultra-fine (alccofine) material accelerates the hydration of cement particles and subsequently improves the mechanical and durability properties of the concrete at normal temperature. Moreover, at higher temperatures th...

In this paper, the sorption isotherm and the hygral deformation of a tensile strain-hardening fiber reinforced engineered cementitious composite (ECC) is described using a physical model. The influence of using a low alkali content Portland cement on the physical mechanisms of drying shrinkage is discussed. From a durability point of view the crack width of a material as a result of restrained ...

This paper describes a symmetric ultra lowvoltage (ULV) rail-to-rail CMOS amplifiers using floating gates. Simulation of a compact differential ULV amplifier is presented.

Some Problems on High Strength Concrete for Prestressing by Kanji YAMAZAKI (Research Laboratory of Nihon Cement Co., Ltd., Tokyo) This paper describes some problems on high strength concrete studied in our laboratory in recent years. Summary of this report is as follows: (1) In order to make high strength concrete for prestressing, it is necessary to lower the water-cement ratio. But, in the ca...

A composite hip prosthesis (CHP) made from alumina reinforced ultra high molecular weight polyethylene (UHMWPE) was designed and manufactured. The main objective of the study was to fabricate the composite hip prosthesis which would be an ideal replacement of metallic one as bone is a composite material consisting of collagen fibre matrix and embedded hydroxyapatite mineral. With this idea we d...

In this study, we evaluated a two-step process for detoxification of waste roofing slate, involving cement hydrate removal and low temperature detoxification using oxalic acid. These treatments were conducted on raw material and intermediate product, respectively. Cement hydrate removal effectively eliminated most Ca-containing cement hydrate components from the raw material under the following...

in modern endodontics, vital pulp therapy (vpt) has been considered an ultra-conservative treatment modality. based on the level of pulp preservation, vpt includes stepwise excavation, indirect pulp capping (idpc), direct pulp capping (dpc), miniature pulpotomy (mp), partial/cvek pulpotomy and coronal/complete pulpotomy (cp). the present article reviews the treatment outcomes of 94 permanent te...

Superplasticizers are a class of anionic polymer dispersants used to inhibit aggregation in hydraulic cement, lowering the yield stress of cement pastes to improve workability and reduce water requirements. The plant-derived biopolymer lignin is commonly used as a low-cost/low-performance plasticizer, but attempts to improve its effects on cement rheology through copolymerization with synthetic...

This paper reports the effects of carbon nanofibers (CNFs) on nanoscaled mechanical properties of cement composites. CNFs were added to cement composites at the filler loading of 0.2 wt % (by wt. of cement). Micrographs based on scanning electron microscopy (SEM) show that CNFs are capable of forming strong interfacial bonding with cement matrices. Experimental results using nanoindentation rev...

Ultra-High Performance Concrete (UHPC) improves the bearing capacity as well durability of structural concrete. This study aims to investigate constituents UHPC in both phases: aggregate and cementitious materials. The proper ratio mixture was chosen based on combining an gradation quartz sand crushed stone. In addition, compressive strength hardened cement paste investigated achieve optimal si...