ABSTRACT  Introduction: Recently uses of medium and high energy x-rays has been increased in Iran and radiotherapy centers along with a variety of accelerators have been installed in some provinces. In the other hand there is no sufficient skill in designing and making radiotherapy treatment rooms. This study was conducted to evaluate the efficacy of different m...

Utilization of pozzolanic materials (fly ash, slag, zeolite, metakaolin, microsilica and more) in the manufacturing of cement and concrete has increased considerably over the last decades. Another option is to use concrete containing sulfate resisting cement. This could help minimize the harmful impacts on concrete exposed to an aggressive environment. The issue of the deteriorative impact of t...

Sand-cement emerged in the early twentieth century as an alternative binder in infrastructures that required a significant amount of concrete volume in order to reduce the costs associated with portland cement. This binder was first used in the United States in several dams before being applied in Camarasa Dam in Spain. Nearly a century after its construction, the dam exhibits degradation pheno...

Compressive strength and concrete slump are the most important required parameters for design, depending on many factors such as concrete mix design, concrete material, experimental cases, tester skills, experimental errors etc. Since many of these factors are unknown, and no specific and relatively accurate formulation can be found for strength and slump, therefore, the concrete properties ca...

Abstract—The main objective of this paper is study the influence of carbon nano-tubes fibers and nano silica fibers on the characteristic compressive strength and flexural strength on concrete and cement mortar. Twelve tested specimens were tested with square section its dimensions (4040 160) mm, divided into four groups. The first and second group studied the effect of carbon nano-tubes (CNT...

Two groups of concrete mixtures, one without sodium sulfate and other with sodium sulfate, as an activator, were made with recycled powdered gypsum-wallboard for this investigation. Group 1 concrete mixtures were made using up to 20% of ASTM Class C fly ash and 20% powdered gypsum while Group 2 contained up to 60% of fly ash and 20% of powdered gypsum by mass. Relevant properties of concrete we...

Green concrete are generally composed of recycling materials as hundred or partial percent substitutes for aggregate, cement, and admixture in concrete. To reduce greenhouse gas emissions, efforts are needed to develop environmentally friendly construction materials. Using of fly ash based geopolymer as an alternative binder can help reduce CO2 emission of concrete. The binder of geopolymer con...

Abstract Several factors, such as chemical shrinkage or environmental attack can produce concrete cracks. Calcium hydroxide content from the environment cement hydration promote self-healing phenomenon (SHP). This study evaluates calcium concentration influence on of cement-based materials. Cracked mortars with different types cement, a filler, pozzolanic, and high initial strength, were expose...

Pozzolans have been used to improve the some properties of concrete and also to reduce the cost of producing cement. Many researchers investigated pozzolanic cements, which were mostly made with kind of artificial or natural pozzolans. While the most recent investigations on pozzolan containing cements study the effect of pozzolan type, replacement amount and fineness, this study was investigat...

High performance concrete is not only characterized by its high strength, workability, and durability but also by its smartness in performance without human care since the first day. If the concrete can cure on its own without external curing without compromising its strength and durability, then it is said to be high performance self-curing concrete. In this paper, an attempt is made on the pe...