Tensile behavior of reactive powder concrete

مقدم أطروحة جامعية

Danha, Lubna Salim

مشرف أطروحة جامعية

al-Husni, Hisham Muhammad
Khalil, Wasan Ismail

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة البناء و الإنشاءات

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2012

الملخص الإنجليزي

A new generation of Ultra High Performance Concrete (UHPC) named Reactive Powder Concrete (RPC) was developed in the last decades, which offers, superior strength, durability and ductility.

One of the main differences between other concretes and RPC is that the latter requires mechanical models capable of taking tensile behavior into account for structural application to enable the material to be fully exploited.

The present research represents an experimental and theoretical contribution to the understanding of the tensile and bending behavior of RPC.

An experimental investigation is carried out to specify and investigate some mechanical properties of RPC which are particularly required as input data for structural design.

These properties include compressive strength, direct tensile strength, splitting tensile strength, flexural tensile strength, flexural toughness and static modulus of elasticity.

In addition, the complete stress-strain relationships in tension and compression of RPC are established and general equations for expressing such relationships are obtained.

On all these properties of RPC which are investigated in this research, the effects of three variable parameters are carefully studied and discussed which are the superplasticizer type (Sikament®-163N and PC200), silica fume content SF (0%, 10%, 15%, 20%, 25%, and 30%) and steel fibers volume fraction Vf (0%, 1%, 2% and 3%).

Proposed expressions relating the mechanical properties of RPC with each other are established in this research using the technique of regression analysis based on the data obtained from the present research work.

And finally analytical study is devoted to establish a simple equation for predicting the nominal bending moment capacity (Mn) of singly reinforced rectangular RPC sections.

The proposed Mn equation is derived based on idealized stress blocks for both compression and tension.

The experimental results indicated that using PC200 in an RPC mix rather than Sikament®-163N gave a much lower w/cm ratio.

Accordingly the cylinder compressive strength, direct tensile strength, splitting tensile strength and flexural tensile strength with PC200 were higher by 12.97%, 6.30%, 7.59%, and 9.18% respectively than that with Sikament®-163N admixture.

It was found from the experimental test results that increasing the steel fibers volume fraction Vf from 0% to 3% and the silica fume content SF from 0% to 30% increase the cube compressive strength by 9% and 34%, cylinder compressive strength by 12% and 41%, direct tensile strength by 238% and 17%, splitting tensile strength by 258% and 16% and flexural tensile strength by 217% and 19% respectively.

The experimental results of the compressive stress-strain relationship obtained for different RPC mixes, showed that increasing the silica fume content caused the ascending part of the compressive stress-strain curve to become steeper giving higher modulus of elasticity as well as an apparent increase in compressive strength, but there was no clear effect on the value of its corresponding strain.

It was also found that the addition of steel fibers slightly increased the slope of the ascending portion of the stress-strain curve, but there was a clear increase in strain at peak stress and an increase in ductility.

With regard to the tensile stress-strain relationship of RPC, it was found that the three main variables of the present investigation had no significant effect on the shape of the ascending part of the stress-strain curve, while the descending part of the curve was found to be considerably affected by the volume fraction Vf of the steel fibers used.

Increasing Vf from 0% to 3% resulted not only in increasing the area under the tensile stress–strain curve, but also increased both the maximum tensile strength from 3.64 to 12.32 MPa and its corresponding strain from 0.00009 to 0.00373.

Two nonlinear equations are suggested in this research to model the ascending and descending part of the tensile stress-strain relationship which are found suitable to represent the tensile behavior of the RPC mixes.

A simple and accurate equation for the prediction of the nominal bending moment capacity Mn of plain and singly reinforced rectangular RPC sections is derived which shows good agreement with the flexural test results performed in the present research and some previous investigations on RPC beams.

التخصصات الرئيسية

العلوم الهندسية والتكنولوجية (متداخلة التخصصات)

الموضوعات

• الخرسانة
• الخواص الميكانيكية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-419819