the main purpose of cementing of the well is to provide effective zonal isolation for the entire life of wells. the standard cements cannot prevent loss of zonal isolation when the stress level in the well cement is severely fluctuated. since elastic cements improve elastic properties, recently, a number of studies have been done in this area. for this purpose, a nanoparticle, named ex-ripi, wa...

in the present investigation, for the first time in iran, dewatered sludge waste from air heater washing wastewater treatment of a thermal power plant was subjected to investigation of the cement base stabilization and solidification experiments in order to reduce the mobility of heavy and other hazardous metals as well as increasing the compressive strength of the solidified product for possib...

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...

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...

This study was conducted to evaluate the properties of cement bonded particleboard made from rice husk and sawdust. Sawdust and rice husk fine boards were made using two ratios of cement and particles of 70:30 and 80:20, but rice husk coarse was made with a ratio of cement and particle of 80:20. The density of sawdust and rice husk fine boards in a ratio of cement and particles of 70:30 was 960...

This study experimentally investigates the effect of multi-walled carbon nanotubes (MWNT’s), as a reinforcing material, on the physical properties of heavy-weight oil well cements. A candidate well is selected and the properties of the cement slurry used in a problematic section of the well are tested in the laboratory. Carbon nanotubes (CNT’s) are added as fibers to the cement slurry and the i...

In this study, the effect of cement content on concrete performance in corrosive environments is investigated on concrete mixtures having the same water/cement (w/c) ratio. Three w/c ratios (0.40, 0.45 and 0.50) were used and for each w/c ratio three mixtures were prepared with cement contents 350, 400 and 450 kg/m3. The compressive strength, electrical resistivity and chloride diffusivity of t...

This paper deals with the issues of air entraining and water/cement ratio in Portland Cement Concrete as related to its freeze thaw durability. Practices have been in place for nearly thirty years which demanded high early strengths in Portland Cement Concrete pavements. This paper looks at those practices, investigates the correlation between water/cement ratio and air entraining, and presents...

Recent tendencies in concrete technology have been towards to high- performance concrete with a low water-cement ratio. However, high performance concretes have some problems. One of the problems is early-age cracking due to autogenous shrinkage. This study presents the results of an experimental investigation carried out to evaluate the autogenous shrinkage of high-strength concrete. Accordi...

This paper presents the compressibility of tropical peat reinforced with cylindrical cement columns. When a cement column is installed vertically in peat, its compressibility is reduced because of the hardened skeleton matrix formed by cement particles bonding with adjacent soil particles in the presence of pore water. The effects of the cement column diameter on the compressibility have been i...