The properties and mesco/microstructure characteristics of interfacial zone between precast concrete and self-compacting concrete

2021 ◽  
Vol 297 ◽  
pp. 123753
Author(s):  
Wenxu Li ◽  
Youjun Xie ◽  
Kunlin Ma ◽  
Guangcheng Long ◽  
Ning Li ◽  
...  
2018 ◽  
Author(s):  
erniati ◽  
muhammad wihardi tjaronge ◽  
Rudy Djamaluddin ◽  
Victor Sampebulu

Indonesia is an archipelagic country which makes many areas doesn’t have qualified water as drinking water. As concrete construction building in the region has possibly minimum or non-existent amount of fresh water, the using of sea water in mixing concrete and curing concrete is unavoidable. The demand of water is getting more and more increasing in both the improvement of infrastructure development and the life need. In the concrete industry, several billion tons of water is used as water mixing, curing and cleaning every year. Therefore the use of sea water is not allowed. In fact, we know that seawater is one of the abundant natural resources. Due to this problem, the research on the use of sea water is very important owing to the saving of freshwater is seriously needed. This study uses sea water by combining effective and efficient concrete technology of Self Compacting Concrete (SCC). This paper is a part of ongoing research studying about microstructure characteristics and the strength of SCC using sea water. It discusses about the compressive strength, absorption and porosity as microstructure characteristics of SCC until the age of 28 days. The results are: (1) the seawater used as mixing water did not affect the development of the compressive strength of concrete, (2) the difference compressive strength of SCC-SS with SCC-FF at an early age is very high occurred at ages 1 and 3 days and (3) The higher the compressive strength value is, the smaller the absorption and porosity is in concrete.


Author(s):  
Simon KAPRIELOV ◽  
Andrey SHEYNFELD ◽  
Igor ARZUMANOV ◽  
Igor CHILIN

The information about the new national standard GOST R «Self-compacting concrete mixtures. Specifications», developed by the «Research Institute for Concrete and Reinforced Concrete» named after A.A. Gvozdev, of JSC «Research Center of Construction», is presented. The standard applies to ready-to-use selfcompacting concrete mixtures of heavyweight, fine-grained, light-weight and reactive powder concretes, as well as fiber reinforced concretes, for the production of monolithic or precast concrete structures and products, the shape and reinforcement of which makes it difficult to place and compaction of an ordinary concrete mixture. The standard establishes new terms and definitions, types and designations, uniform requirements for new technological characteristics (slump-flow, segregation, viscosity and flowability), acceptance rules and test methods, production and transportation processes, control and evaluation procedures conformity of quality indicators of self-compacting concrete mixes.


2018 ◽  
Author(s):  
erniati ◽  
muhammad wihardi tjaronge ◽  
Rudy Djamaluddin ◽  
Victor Sampebulu

In the cycle of life, the needs of freshwater more and more. Infrastructure development is increasing. On the concrete industry, several billion tones of water used in earth as mixing water, treatment water (curing) and cleaner water every year, where using of sea water is obstructed. For that, the using of sea water which consists of 97% of the total water on earth is absolutelynecessary. Self-compacting concrete (SCC) has dense microstructure. Knowledge about the microstructure and properties of each component a concrete and their relationship is useful to control the behavior. This research aims to know the relationship between compressive strength and microstructure characteristics of Self Compacting Concrete which using seawater up to the age of 90 days. The results of this study were the compressive strength of SCC using sea water is higher than the SCC using fresh water. Seawater does not reduce the strength of SCC concrete until the age of 90 days, but instead of Seawater is accelerating the development of SCC concrete strength at an early age. The compressive strength of concrete SCC is influenced by the phase microstructure (especially with tobermorite and portlandite) formed in the concrete.


2017 ◽  
Vol 153 ◽  
pp. 364-373 ◽  
Author(s):  
Ángel Salesa ◽  
Jose Ángel Pérez-Benedicto ◽  
Luis Mariano Esteban ◽  
Rosa Vicente-Vas ◽  
Martín Orna-Carmona

2020 ◽  
Vol 10 (20) ◽  
pp. 7348
Author(s):  
F. Fiol ◽  
C. Thomas ◽  
J. M. Manso ◽  
I. López

The research presented in this article analysed the influence of incorporating precast concrete waste as an alternative to coarse aggregate in self-compacting concrete to generate new precast elements. The experimental study involved the characterization of recycled aggregate and the design of the mix of the new self-compacting concrete (SCC). The experimental study evaluates the physical processes that affect the durability of concrete with percentages of incorporation such as 20%, 50% and 100% of recycled aggregate. Two types of SCC were manufactured with minimum compressive strength of 30 MPa and 45 MPa. The properties analysed were density of hardened SCC, shrinkage cracking, freeze-thaw resistance, resistance to ageing by thermal shock and abrasion resistance. The results obtained were compared with those of the control concrete, observing great capacity of the SCC under physical aggressions that affect durability. The results of this research show that it is possible to use the recycled aggregate coming from precast pieces in order to the manufacture of self-compacting recycled concrete in the same precast industry. However, high loss of proprieties occurs for a 100% substitution, while for 20% and 50%, the variations with respect to control concrete are smaller. In addition, taking advantage of this waste to incorporate it back into the production chain contributes to more sustainable construction.


2019 ◽  
Vol 10 (4) ◽  
pp. 515-533
Author(s):  
Faeze Nejati ◽  
Samira Ahmadi ◽  
S.A. Edalatpanah

Purpose Modern construction methods have been developed with the goal of reducing construction time as much as possible, which results in some situations during construction and within the first few days after it, when concrete is subjected to exceptionally high loads. The precast concrete, which is the concrete in very early ages, may result in severe cracks or damages. In conventional construction projects, sometimes working with concrete, which had not reached its ultimate strength, is an unavoidable matter of fact. This paper aims to discuss these issues. Design/methodology/approach Researchers in the field of construction materials have done their best to make some changes in the different parts of the concrete in order to bring about reforms, based on the existing needs, and achieve new quality and primacy from concrete. One kind of concrete, the emergence of which dates back to many years ago, is self-compacting concrete. Thanks to its high efficiency for the parts with complex forms of high-density steel, this kind of concrete suggests new prospects. Findings This study aims at evaluating the effect of early loads on the 28-day compressive strength of concretes with zeolite and limestone powder under different curing conditions (wet or dry). In this regard, two self-compacting concrete mix designs with the same ratio of water to cementations materials and 0.4 percent and 10 percent zeolite have been considered; therefore, concrete cube samples with zeolite and limestone powder in different curing conditions at ages of three, one and seven days under preloading with 80–90 percent of compressive strength are damaged, and after curing in different conditions, their 28-day compressive strength is measured. According to the results, the recovery of the 28-day compressive strength of damaged samples, compared to that of intact samples, is possible in all curing conditions. The experiments that have been performed on concrete samples under dry and wet curing conditions show that the full recovery of compressive strength of damaged samples compared to that of intact ones happened only in preloaded samples at the age of one days, and in other ages (three and seven days) the 28-day strength reduction has occurred in damaged samples compared to the that in intact samples. The results of concrete samples with zeolite and without limestone powder at the age of one day indicate the greatest impact on other samples on the 28-day compressive strength of damaged samples compared to that of intact ones, occurring under dry condition. Originality/value This research analyzed and studied the influence under wet and dry curing conditions and the presence of limestone powder and zeolite fillers in recovering of the 28-day compressive strength of preloaded concrete samples at early stages (one, three and seven days) after the construction of the concrete.


2018 ◽  
Vol 30 (10) ◽  
pp. 451-468 ◽  
Author(s):  
Madduru Sri Rama Chand ◽  
Pancharathi Rathish Kumar ◽  
Pallapothu Swamy Naga Ratna Giri ◽  
Garje Rajesh Kumar

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Wael Zatar ◽  
Tu Nguyen

In recent years, there has been an increasing demand to produce strong precast street light posts that are aesthetically pleasing. This study presents experimental results of a considerable number of mixture designs for fabricating precast street light posts where fiber-reinforced self-compacting concrete (FRSCC) was employed. The performance of many FRSCC mixtures was evaluated in terms of their structural properties and aesthetic characteristics. A trial-and-error procedure was performed for a series of FRSCC mixtures where silica fume, fly ash, and fibers were used. Slump flow and air content tests were conducted to determine the fresh FRSCC properties, and specimens were cast to evaluate their aesthetic. Three-day and seven-day compression tests were performed to examine the FRSCC hardened properties. The amount of cement in all batches was kept constant, whereas the distributions of fine and coarse aggregates, water, and other admixtures were adjusted. The largest slump flow of 73.7 cm (29 in) was recorded, and the maximum three-day compressive strength was 43 MPa (6209 psi). Further refinement of the mixtures, which displayed the best strength and aesthetic attributes, was performed. Test results of the selected FRSCC mixtures indicated an excellent slump flow, air content, and compression values while achieving advantageous aesthetic qualities. Seven-day compressive strength of 39 MPa (5686 psi) with the air content of 4.8 percent and the slump flow of 66 cm (26 in) was recorded. The study results and the developed FRSCC mixes can be used for mass production of precast concrete street light posts in precast plants.


2020 ◽  
Vol 24 (06) ◽  
pp. 22-32
Author(s):  
Ahmed H. Hashim ◽  
◽  
Waleed A. Wrayosh ◽  

The main objective of this research is to study the effect of carbon fibers used to strengthen the joints of the box segmental beams. For this research, four beams were produced and tested. One of these beams, monolithically, was cast as a reference beam and the three others were segmental beams. All beams were produced with Self-Compact Concrete (SCC) and box cross section. Each segmental beam consisted of three precast concrete segments were connected by post tensioning tendons. The three segmental beams have same characteristics, but different in joint types between the segments. The types of joints used were (dried , epoxied and dried strengthen by CFRP sheets). All beams were tested under static two point loads up to failure. For each test, deflections at mid-span location were recorded for each (5kN). Also, first cracking, mode of failure and ultimate loads values were recorded as well as the concrete surface strains at the specified locations for both loadings.


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