Research of Performance of Low Amount of Cement Manufactured-Sand Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1200-1205
Author(s):  
Chun Hui Yu ◽  
Gu Hua Li ◽  
Jin Liang Gao ◽  
Qun Wei ◽  
Da Zhen Xu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Grain Shape ◽  
Great Influence ◽  
Cementitious Materials ◽  
Natural Sand ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Manufactured Sand

Compared with natural sand, manufactured-sand is of small porosity, poor grain shape and graded, which impacts mixes workability and the properties after hardening. In Concrete, playing the role of retaining moisture water is mainly powder, including cement, powder in the sand and fly ash etc. The amount of powder has a great influence on the properties of concrete, especially on its workability. This paper mainly discusses the influence of amount of cement, cementitious materials, fly ash, water-cement ratio and other factors on the workability, compressive strength and shrinkage of concrete. The experiments show that, in the case of the low amount of cement, workability of the manufactured-sand concrete mixture, compressive strength and shrinkage deformation of test block all meet the actual requirements.

scholarly journals Influence of boulder machine-made sand powder on compressive strength of concrete

2021 ◽  
Vol 293 ◽  
pp. 02023
Author(s):  
Pengtao Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Early Stage ◽  
Cementitious Materials ◽  
Mineral Admixtures ◽  
Rock Powder ◽  
Manufactured Sand ◽  
Slag Powder ◽  
Compressive Strength Of Concrete ◽  
Curing Age

In order to recycle the boulder powder produced in the process of manufactured sand production and reduce the cost of engineering concrete, this article studied the influence of boulders powder on the compressive strength of concrete. The results show that in the early stage of concrete test, the compressive strength of rock powder concrete is slightly lower than of fly ash and mineral powder concrete. With the development of curing age, the strength of boulders powder concrete developed slower. As the increase of boulders powder content, the compressive strength of different curing age gradually decreased, and it was suggested that the content of boulders powder should be controlled within 20% of cementitious materials mass. The positive effect of boulders powder fineness on the strength of concrete is limited, so it is suggested to use unprocessed collected boulders powder in the project, which is economical and environmentally friendly. With the adjustment of water-to-binder ratio, boulders powder can be prepared with different strength grades of concrete to meet the needs of engineering; the composite of boulders powder with traditional mineral admixtures, such as fly ash, and especially granulated blast furnace slag powder, can significantly improve the strength of concrete.

scholarly journals The Assessment of Strength of Cementitious Materials Impregnated Using Hydrophobic Agents Based on Near-Surface Hardness Measurements

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4583
Author(s):  
Martyna Nieświec ◽  
Łukasz Sadowski
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Concrete Structures ◽  
Surface Hardness ◽  
Cementitious Materials ◽  
Schmidt Hammer ◽  
Near Surface ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Impact

Recently, the surfaces of concrete structures are impregnated to protect them against the environment in order to increase their durability. It is still not known how the use of these agents affects the near-surface hardness of concrete. This is especially important for experts who use the near-surface hardness of concrete for estimating its compressive strength. The impregnation agents are colorless and, thus, without knowledge of their use, mistakes can be made when testing the surface hardness of concrete. This paper presents the results of investigations concerning the impact of impregnation on the subsurface hardness concrete measured using a Schmidt hammer. For this research, samples of cement paste with a water–cement ratio of 0.4 and 0.5 were used. The samples were impregnated with one, two, and three layers of two different agents. The first agent has been made based on silanes and siloxanes and the second agent has been made based on based on polymers. The obtained research results allow for the conclusion that impregnation affects the near-surface hardness of concrete. This research highlights the fact that a lack of knowledge about the applied impregnation of concrete when testing its near-surface hardness, which is then translated into its compressive strength, can lead to serious mistakes.

Microscopic Mechanism of the Diffusivity of Concrete Chloride Ion

2013 ◽  
Vol 773 ◽  
pp. 687-692 ◽  
Author(s):  
Jun Liu ◽  
Feng Xing ◽  
Bi Qing Dong
Keyword(s):  
Fly Ash ◽  
Early Stage ◽  
Great Influence ◽  
Chloride Ion ◽  
Test Method ◽  
Mineral Admixture ◽  
Microscopic Mechanism ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Impact

Use concrete specimens with different mix proportions to conserve them for 90d taking into account the influence of mineral admixture material---fly ash. Then adopts the RCM test method to measure the rapid diffusivity of chloride ion of concrete and observes the microstructure of the cement paste using the SEM (scanning electron microscopy), aiming to study the impact of fly ash on its hydration process. The results show that the micro-pore structure of the concrete has a great influence on the rapid diffusivity of chloride ion, while its diffusivity is closely related with the water-cement ratio of concrete; after the fly ash is added, the ettringite generation of the concrete in the early stage decreases, and the interspace of the transition zone between the hydrated particles and hydration slurry is enlarged, coupled with the increase in the intercommunicating pore; after curing for 90d, the chloride ion diffusivity decreases significantly with the increase in the dosage of fly ash. For the concrete with the fly ash dosage of 15%, its chloride ion diffusivity is only 75.4% of that with the same water-cement ratio; when its fly ash content is 30%, its chloride ion diffusivity is only 32.3% of the ordinary concrete.

Evaluation of Fly Ash on the Basis of Mass Equivalent, Maturity Equivalent and Permeance

1985 ◽  
Vol 65 ◽  
Author(s):  
R. H. Mills
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Gas Flow ◽  
Concrete Mixture ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Efficiency Factors ◽  
Gas Tightness

ABSTRACTCombinations of two types of commercially available Fly Ash (FA) and Portland cement (PC) were tested for compressive strength and permeance to gas flow. The cementitious components were combined in the concrete mixture in proportions PC/FA = 100/0, 75/25, 60/40 and 45/55 for a range of water/cement ratio, and equal workability. Strength and maturity efficiency factors were satisfactory for 75/25 and 60/40 blends. Gas tightness was improved at all levels of Fly Ash substitution.

Research on Static Compressive Experiment of Concrete Mixed with Limestone Power and Fly Ash

2013 ◽  
Vol 405-408 ◽  
pp. 2801-2805
Author(s):  
Ji Feng Liang ◽  
Lei Lv ◽  
Feng Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Test Method ◽  
Limestone Powder ◽  
Experimental Result ◽  
Enhancement Effect ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Orthogonal Test Method ◽  
Powder Content

The use of orthogonal test method, the concrete mixed with limestone power and fly ash was carried out static compressive experiment, and contrast with the experiment of single doped with limestone powder and fly ash concrete. The experimental result demonstrated that the compressive strength enhancement effect of the concrete mixed with limestone power and fly ash was obvious. The importance of each factor affecting static compressive strength as follows: water-cement ratio, the amount of fly ash, the amount of limestone powder, sand ratio. The concrete compressive strength reached the maximum when the water-cement ratio reached 0.3, the limestone powder content reached 15%, the fly ash content reached 10%, and sand ratio reached 34%.

Study of Manufacture Process and Properties of Tailings and Slag Based Mine Filling Cementitious Materials

2013 ◽  
Vol 734-737 ◽  
pp. 1077-1081 ◽  
Author(s):  
Jin Xia Zhang ◽  
Shu Xian Liu ◽  
Jun Xie
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Raw Materials ◽  
Cementitious Materials ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Manufacture Process ◽  
Alkali Activated

The tailings and slag based mine filling cementitious materials was prepared by sodium silicate and sodium hydroxide alkali-activated tailings and slag. Through the test that the cementing materials in the best ratio of raw materials: when slag and tailings admixture is 1.25, the content of NaOH was 50%, the amount of sodium hydroxide for 50%, water cement ratio of 0.22, under the condition of normal temperature curing 7 days, eventually making a compressive strength of 52.3MPa cementing materials.

scholarly journals Influence of Pore Structure on Compressive Strength of Cement Mortar

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Haitao Zhao ◽  
Qi Xiao ◽  
Donghui Huang ◽  
Shiping Zhang
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Cement Mortar ◽  
Natural Sand ◽  
Cement Ratio ◽  
Manufactured Sand ◽  
Mix Proportion ◽  
Mercury Porosimeter ◽  
Threshold Radius

This paper describes an experimental investigation into the pore structure of cement mortar using mercury porosimeter. Ordinary Portland cement, manufactured sand, and natural sand were used. The porosity of the manufactured sand mortar is higher than that of natural sand at the same mix proportion; on the contrary, the probable pore size and threshold radius of manufactured sand mortar are finer. Besides, the probable pore size and threshold radius increased with increasing water to cement ratio and sand to cement ratio. In addition, the existing models of pore size distribution of cement-based materials have been reviewed and compared with test results in this paper. Finally, the extended Bhattacharjee model was built to examine the relationship between compressive strength and pore structure.

Experimental Study on Strength of Recycled Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1282-1285
Author(s):  
Hai Yong Cai ◽  
Li Bin Fu ◽  
Ling Bo Dang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Great Influence ◽  
Recycled Concrete ◽  
Replacement Ratio ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Concrete Mechanical Properties

Influence of replacement ratio and water-cement ratio on the recycled concrete mechanical properties were analyzed by testing the compressive strength and tensile strength of the recycled concrete. Results show that the mechanical properties of recycled concrete, compared with common concrete, can meet the requirements of the project. Water-cement ratio has great influence on compressive strength and tensile strength, replacement ratio has obvious influence on compressive strength but little on tensile.

scholarly journals Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Suhana Koting ◽  
Mohamed Rehan Karim ◽  
Hilmi Mahmud ◽  
Nuha S. Mashaan ◽  
Mohd Rasdan Ibrahim ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Strength ◽  
Flexible Pavement ◽  
Cementitious Materials ◽  
Flow Properties ◽  
Cement Ratio ◽  
Paired Sample ◽  
Water Cement Ratio ◽  
Porous Pavement

Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-samplet-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout.

Pastes Prepared with Sulfonate, Chalcedony and Sugar

2012 ◽  
Vol 517 ◽  
pp. 338-341
Author(s):  
Ulisses Targino Bezerra ◽  
Normando Perazzo Barbosa
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Compression Strength ◽  
Cementitious Materials ◽  
Important Conclusion ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Good Workability ◽  
Portland Cement Paste

Papers presented at ICPIC 2010, Madeira Island, Portugal, dealing with the use of polymers in cementitious materials, show the need to combine different admixtures to optimize the properties of cement. This work is a continuation of a paper presented at NOCMAT 2010, Cairo-Egypt, about the incorporation of several materials in Portland cement to increase mechanical properties and workability. The best performance admixtures were chosen and they were combined considering the superposition of effects. Cement pastes were prepared with chalcedony and sulfonate (to increase compressive strength) and sugar (to increase workability). Two percent of cement was replaced by the admixtures. The water/cement ratio was constant and equal to 0.44. Results show that the combination of 0.05% of sugar and 1.95% of sulfonate and 0.10% of sugar and 1.90% of chalcedony produced a paste with the greatest compressive strength and good workability. Compression strength was respectively 27.4 MPa and 36.6 MPa, which represent increases of 33.5% and 78.6%, respectively, relative to the reference paste without admixtures. While increasing the paste compression strength with sulfonate has been significant, the results of the paste with chalcedony were the more surprising because the water/cement ratio of pastes was kept constant. The chalcedony is a type of crystalline silica, which shows deformation in their structure. So because of crystalline structure of chalcedony, there should be, probably, no significant reactivity of it with the cement hydrates, just the fact that its structure be deformed can explain this reactivity. The most important conclusion concerns is that the combinations of admixtures can improve a lot the properties of Portland cement paste.

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