Evaluation of the mechanical properties and scaling durability of high strength lightweight concrete

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Evaluation of the mechanical properties and scaling durability of high strength lightweight concrete

ارائه دهنده: Provider: alireza abdolahzadeh

اساتید راهنما: Supervisors: dr. mahmood nili

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Dr. mostafa moghadasi, Dr seyed mehdi hoseinian

زمان و تاریخ ارائه: Time and date of presentation: 9/17/2023

مکان ارائه: Place of presentation: seminar 2

چکیده: Abstract: One of the strategic goals of the construction industry, especially in earthquake-prone zones such as Iran, is lightening of structures and achieving this goal is of paramount importance. Nowadays, durability and longer life span of structures have been taken into account in the design of structures. Therefore, it's crucial to consider how high strength lightweight concrete performs in cold climates, especially when deicing salt is present.t is worth mentioning that lower mechanical properties of lightweight concrete led to concerns about using it in structures. The aim of this study is investigating the effects of Scoria on mechanical properties and scaling durability of high strength lightweight concretes. In this research, compressive strength, tensile strength, modulus of elasticity and degree of scaling have been measured. 8 mix designs with a cement to ratio of 0.35 were designed. Silica fume (10%) and slag (25 and 45%) have been used as pozzolans. Furthermore, an air entraining agent was used in some lightweight mixes to produce deliberate air bubbles. The results show that the density of lightweight concrete was reduced by the replacement of Scoria to 2000kg/m3 and even 1920kg/m3 in some mixtures. The compressive strength of each concrete mix was greater than 40MPa.The use of silica fume contributes to a rise in the compressive strength, while slag had negligible effect on the 28-day compressive strength. Tensile strength was more than the lowest limit of standard (2MPa) and lightweight concretes with pozzolans had higher tensile strength compared to control mix. Replacement of lightweight aggregates resulted in a fall in modulus of elasticity. Moreover, an increase in the compressive strength of lightweight concrete leads to higher modulus of elasticity. Scaling of lightweight concrete was lower than the control mix and pozzolans (slag and silica fume) were effective on scaling resistance.