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CONTENTS
Volume 17, Number 6, June 2016
 

Abstract
A novel approach to modeling concrete behavior at the stage of its maturing is presented in this paper. This approach assumes that at any point in the structure, concrete is composed of a set of layers that are activated in time layer by layer, based on amount of released heat that is produced during process of the concrete

Key Words
concrete; aging; constitutive modeling

Address
Andrzej Truty, Jan Szarliński and Krzysztof Podleś: Department of Environmental Engineering, Cracow University of Technology, ul.Warszawska 24, 31-155 Kraków, Poland

Abstract
In this paper an approach was described for determination of direction of sliding block in rock slopes containing planar non-persistent open joints. For this study, several gypsum blocks containing planar non-persistent open joints with dimensions of 15

Key Words
planar non-persistent discontinuity; rock bridge; effective joint coefficient; tensile and shear cracks

Address
Vahab Sarfarazi:Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran
Hadi Haeri:Department of Mining Engineering, Bafgh Branch, Islamic Azad University, Bafgh, Iran
Alireza Khaloo: Center of Excellence in Structure and Earthquake Engineering, Sharif University of Technology, Tehran, Iran

Abstract
This paper reports on punching shear behavior of reinforced concrete panels, investigated experimentally and through finite element simulation. The aim of the study was to examine the punching shear of high strength concrete panels incorporating different types of aggregate and silica fume, in order to assess the validity of the existing code models with respect to the role of compressive and tensile strength of high strength concrete. The variables in concrete mix design include three types of coarse aggregates and three water-cementitious ratios, and ten-percent replacement of silica fume. The experimental results were compared with the results produced by empirical prediction equations of a number of widely used codes of practice. The prediction of the punching shear capacity of high strength concrete using the equations listed in this study, pointed to a potential unsafe design in some of them. This may be a reflection of the overestimation of the contribution of compressive strength and the negligence of the role of flexural reinforcement. The overall findings clearly indicated that the extrapolation of the relationships that were developed for normal strength concrete are not valid for high strength concrete within the scope of this study and that finite element simulation can provide a better alternative to empirical code Equations.

Key Words
punching shear; high strength concrete; coarse aggregate type; silica fume; finite element simulation

Address
Ahmed B. Shuraim, Fahid Aslam, Raja R. Hussain and Abdulrahman M. Alhozaimy: Civil Engineering Department, College of Engineering, King Saud University, Riyadh, Saudi Arabia

Abstract
This paper proposes an automated procedure for optimum seismic design of reinforced concrete (RC) frame structures. This procedure combines a smart pre-processing using a Tree Classification Method (TCM) and a nonlinear optimization technique. First, the TCM automatically creates sections database and assigns sections to structural members. Subsequently, a real valued model of Particle Swarm Optimization (PSO) algorithm is employed in solving the optimization problem. Numerical examples on design optimization of three low- to high-rise RC frame structures under earthquake loads are presented with and without considering strong column-weak beam (SCWB) constraint. Results demonstrate the effectiveness of the TCMin seismic design optimization of the structures.

Key Words
automated optimum seismic design; reinforced concrete structure; tree classification method; construction cost; strong column-weak beam; particle swarm optimization

Address
Sadjad Gharehbaghi:Department of Civil Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran
Abbas Moustafa: Department of Civil Engineering, Minia University, Minia 61111, Egypt
Eysa Salajegheh: Department of Civil Engineering, Shahid Bahonar University of Kerman, Kerman, Iran

Abstract
Climate anomalies in recent years, numerous natural disasters caused by landslides and a large amount of entrained sands and stones in Taiwan have created significant disasters and greater difficulties in subsequent reconstruction. How to respond to these problems efficaciously is an important issue. In this study, the sands and stones were doped with recycled materials (waste LCD glass sand, slag powder), and material was mixed for recycled ready-mixed soil. The study is based on security and economic principles, using flowability test to determine the water-binder ratio (W/B=2.4, 2.6, and 2.8), a fixed soil: sand ratio of 6:4 and a soil: sand: glass ratio of 6:2:2 as fine aggregate. Slag (at concentrations of 0%, 20%, and 40%) replaced the cement. The following tests were conducted: flowability, initial setting time, unit weight, dropweight and compressive strength. The results show that the slump values are 220 -290 mm, the slump flow values are 460 -1030 mm, and the tube flow values are 240-590 mm, all conforming to the objectives of the design. The initial setting times are 945-1695 min. The unit weight deviations are 0.1-0.6%. The three groups of mixtures conform to the specification, being below 7.6 cm in the drop-weight test. In the compressive strength test, the water-binder ratios for 2.4 are optimal (13.78-17.84 kgf/cm2). The results show that Recycled ready-mixed soil materials (RRMSM) possesses excellent flowability. The other properties, applied to backfill engineering, can effectively save costs and are conducive to environmental protection.

Key Words
Recycled Ready-Mixed SoilMaterials (RRMSM); waste LCD glass sand; waste-to-resource

Address
Wen-Ling Huang, Her-Yung Wang and Chen Jheng-Hung: Department of Civil Engineering, National Kaohsiung University of Applied Sciences, 807, Taiwan, R.O.C.

Abstract
An alternative type of building system with masonry units is extensively used nowadays to reduce the emission of CO2 and embodied energy. Long-term performance of such structures has become essential for sustaining the building technology. This study aims to assess the strength and durability properties of concrete prepared with unprocessed bagasse ash (BA) and silica fume (SF). A mix proportion of 1:3:3 was used to cast concrete cubes of size 100 mm

Key Words
concrete; bagasse ash; Silica fume; compressive strength; durability; mass loss

Address
Jayanthi Singaram: Department of Civil Engineering Government College of Technology,Thadagam Road, Coimbatore
Radhika Kowsik: Department of Civil Engineering, Dr.M.G.R, Educational and Research Institute, University Maduravoyal, Chennai



Abstract
This study has been carried out to investigate the effect of the surface properties of Portland cement, diatomite and zeolite on the performance of concrete composites. In this context, to describe the materials used in this study and determine the properties of them, chemical, physical, mineralogical, molecular, thermal, and zeta potential analysis have been applied. In the study, reference (Portland cement), 10%–20% diatomite, 10%–20% zeolite, 5+5%–10+10% diatomite and zeolite were substituted for Portland cement, a total of 7 different cements were obtained. Ultrasonic pulse velocity, capillary water absorption and compressive strength tests were performed on the hardened concrete specimens. Hardened concrete tests have been done on seven different types of concrete, for 28, 56 and 90 days. As a result of experiments it has been identified that both the zeolite and diatomite substitution has a positive effect on the performance of concrete.

Key Words
concrete; diatomite; zeolite; zeta potential; strength

Address
Yilmaz Kocak: Department of Construction, Kutahya Vocational School of Technical Sciences, Dumlupinar University, Kutahya, Turkey

Muhsin Savas: Department of Construction, Institute of Sciences, Duzce University, Düzce, Turkey

Abstract
This study aims to characterize the multiple cracking behavior of HTPP-ECC (High tenacity polypropylene fiber reinforced engineered cementitious composites) by Digital Image Correlation (DIC) Method. Digital images have been captured from a dogbone shaped HTPP-ECC specimen exhibiting 3.1% tensile ductility under loading. Images analyzed by VIC-2D software and

Key Words
fiber reinforced composite; multiple cracking; high tenacity polypropylene fiber; tensile test; digital image correlation

Address
Burak Felekoğlu: Department of Civil Engineering, Dokuz Eylül University, Tinaztepe, Buca, 35397, İzmir / Turkey

Muhammer Keskinateş: The Graduate School of Natural and Applied Sciences, Dokuz Eylül University, İzmir / Turkey


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