Study on the Strength of Sea Sand Concrete in Ningbo

2011 ◽  
Vol 250-253 ◽  
pp. 262-265
Author(s):  
Jun Zhe Liu ◽  
Guo Liang Zhang ◽  
Jian Bin Chen ◽  
Zhi Min He

This paper mainly explain and expounded folding compressive strength of the different types of sea sand mortar , fly ash to the sea sand concretes mortar intensity influence as well as the chloride ion content to the sea sand concretes mortar intensity influence. The pulverized fly ash has the postponement function to the sea sand concretes early strength, the chloride ion has the promoter action to the sea sand concretes early strength. 20% pulverized fly ash be good to the sea sand concretes long-term strength development influence, can achieve the goal which enhances the sea sand concretes the long-term strength . The chloride ion is greater to the concretes early strength influence, especially in previous 3 days. Along with the time development, the chloride ion influence weakens, but the pulverized fly ash enlarges to the concretes intensity's influence factor. A two-phase arrived, the final concrete strength values close to each other.

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ki-Bong Park ◽  
Takafumi Noguchi

The aim of this work is to know clearly the effects of temperature in response to curing condition, hydration heat, and outside weather conditions on the strength development of high-performance concrete. The concrete walls were designed using three different sizes and three different types of concrete. The experiments were conducted under typical summer and winter weather conditions. Temperature histories at different locations in the walls were recorded and the strength developments of concrete at those locations were measured. The main factors investigated that influence the strength developments of the obtained samples were the bound water contents, the hydration products, and the pore structure. Testing results indicated that the elevated summer temperatures did not affect the early-age strength gain of concrete made using ordinary Portland cement. Strength development was significantly increased at early ages in concrete made using belite-rich Portland cement or with the addition of fly ash. The elevated temperatures resulted in a long-term strength loss in both belite-rich and fly ash containing concrete. The long-term strength loss was caused by a reduction in the degree of hydration and an increase in the total porosity and amount of smaller pores in the material.


2012 ◽  
Vol 602-604 ◽  
pp. 962-967 ◽  
Author(s):  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Jang Hwa Lee

In the case of construction with high volume blast-furnace slag(BFS) concrete during winter season, the setting and hardening are drastically delayed, so it has a high risk of initial frost. Assuming that the concrete incorporating a high volume of BFS is affected by freezing at the early age during the winter conditions, then this study is to investigate the effect of curing method on the strength development and the resistance to freezing-thawing action. As a result, the concrete performing water curing at 5°C after subjected to initial frost damage improve the long-term strength and the freezing-thawing durability. The concrete implementing water curing at 30°C enhance the long-term strength and the resistance to freezing-thawing action as well as the early strength. However, the concrete with sealed curing at 30°C exhibits the improvement in the early strength, but not in the long-term strength and the freezing-thawing durability.


1990 ◽  
Vol 12 (4) ◽  
pp. 263-270 ◽  
Author(s):  
V. Sivasundaram ◽  
G.G. Carette ◽  
V.M. Malhotra

2014 ◽  
Vol 1065-1069 ◽  
pp. 1854-1857 ◽  
Author(s):  
Yi Jiang ◽  
Jun Zhe Liu ◽  
Wu Sun ◽  
Chao Yi Zheng ◽  
Si Yun Wu

The harmful chloride ion in sea sand concrete is the main issue that hinders its application, proposing a method using fly ash the active mineral, chloride ion content of harmful curing of sea sand concrete, to improve the durability of sea sand concrete. The experiment studies the influence of sand in the chlorine ion and fly ash on the strength of concrete, and analyzes microscopic structure and hydration products of concrete. Research results show that: the sea sand concrete with 20% fly ash prepared has good mechanical properties and durability; the existence of Cl- on the early strength of sea sand concrete has a positive promoting role, but has negative effective on the later development.


2013 ◽  
Vol 641-642 ◽  
pp. 574-577 ◽  
Author(s):  
Ying Tao Li ◽  
Ling Zhou ◽  
Mao Jiang ◽  
Yu Zhang ◽  
Jun Shao

In this paper, the mechanical property experiments of concrete based on the seawater and sea sand have been carried in different raw materials preparation and different conservation environments. The results show that the early strength and late strength of concrete based on seawater and sea sand are better than concrete based on freshwater and sand. There is no significant strength decreased for concrete based on seawater and sea sand under accelerated alternating wet and dry conditions. For concrete based on seawater and sea sand mixed with admixture, the downward trend of late strength is significantly delayed, the late strength of concrete based on the seawater and sea sand mixed with slag gets the most obvious growth trend, while the late strength of seawater and sea sand concrete mixed with fly ash gets the largest increment.


2019 ◽  
Vol 4 ◽  
pp. 9-15
Author(s):  
Md Shamsuddoha ◽  
Götz Hüsken ◽  
Wolfram Schmidt ◽  
Hans-Carsten Kühne ◽  
Matthias Baeßler

Grouts have numerous applications in construction industry such as joint sealing, structural repair, and connections in precast elements. They are particularly favoured in rehabilitation of structures due to penetrability and convenience of application. Grouts for repair applications typically require high-performance properties such as rapid strength development and superior shrinkage characteristics. Sometimes industrial by-products referred as supplementary cementitious materials (SCM) are used with neat cement due to their capabilities to provide binding properties at delayed stage. Micro silica, fly ash and metakaolin are such SCMs, those can modify and improve properties of cement products. This study aims at investigating long-term mass loss and linear shrinkage along with long-term compressive and flexural strength for grouts produced from ultrafine cement and SCMs. A series of mixtures were formulated to observe the effect of SCMs on these grout properties. Properties were determined after 365 days of curing at 23oC and 55% relative humidity. The effect of SCMs on the properties are characterised by statistical models. Response surfaces were constructed to quantify these properties in relation to SCMs replacement. The results suggested that shrinkage was reduced by metakaolin, while micro silica and fly ash had positive effects on compressive and flexural strength, respectively.


2014 ◽  
Vol 68 (1) ◽  
pp. 523-528
Author(s):  
Makoto SHOJI ◽  
Minoru MORIOKA ◽  
Tomomi YOSHIDA ◽  
Kenichiro NAKARAI

2020 ◽  
Vol 17 (2) ◽  
pp. 1032-1036
Author(s):  
Nur Nadhira Abdul Rasid ◽  
Abdul Rahman Mohd. Sam ◽  
Azman Mohamed ◽  
Nor Hasanah Abdul Shukor Lim ◽  
Zaiton Abdul Majid ◽  
...  

Blended concrete has later strength development with long maturity strength development. An accelerator is thus needed to enhance the early strength development of concrete. This paper shows the combination of ground palm oil fuel ash and eggshell powder that was designed for later and early strength development, respectively. Two types of eggshell powder were utilised in concrete: uncarbonised eggshell powder and decarbonised eggshell powder. The study was initiated with compression test for concrete curing at age 1, 3, 7, and 28 days followed by rapid evaluation test of setting time to investigate the preliminary performance between materials. The results revealed decarbonised eggshell powder as a high accelerator that can improve the early age of concrete strength development. Meanwhile, despite showing the best performance, uncarbonised eggshell powder is a very low accelerator thus not fit the purpose. In conclusion, the combination of ground palm oil fuel ash (rich with silica oxide) and decarbonised eggshell powder (rich with calcium oxide) provided dual function, where ground palm oil fuel ash and decarbonised eggshell powder took later and early strength development, respectively. The combination between silica oxide and calcium oxide in cementitious materials has potential to be utilised to enhance the early age of a blended concrete strength development.


2012 ◽  
Vol 174-177 ◽  
pp. 444-447
Author(s):  
Guo Liang Zhang ◽  
Li Wei Mo ◽  
Jian Bin Chen ◽  
Jun Zhe Liu ◽  
Zhi Min He

Sea sand concrete is a kind of concrete in which mixed sea sand as fine aggregate, which is large-scale application in the coastal areas in recent years, especially in Ningbo area. The sea sand solves the problem of river sand shortage, coupled with cheaper price, most of the ready-mixed concrete companies are willing to use desalted sea sand instead of river sand. Many companies even are using sea sand without any treatments.In Ningbo sea sand concrete using wide range of usage is not optimistic. This survey and analysis in Ningbo area physical characteristics of concrete using sea sand and sea-sand. On this basis, chloride simulating sea sand, mixed with desalted sea sand, not desalted sea sand mortar strength measurement, the concrete strength rule were analyzed, and discovered the early strength for the sea sand concrete by the presence of chloride.


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