scholarly journals THE EFFECTS OF HIGH TEMPERATURE CURING ON HYDRATION REACTION AND STRENGTH DEVELOPMENT OF CEMENT PASTE CONTAINING SILICA FUME AT LOW WATER BINDER RATIO

2013 ◽  
Vol 78 (685) ◽  
pp. 427-433
Author(s):  
Shinichi KOIZUMI ◽  
Yoshihiro MASUDA
2017 ◽  
Vol 25 (1) ◽  
pp. 73-80
Author(s):  
T.H. Chuong ◽  
P.V. Nga

Information of rheological behavior of binder paste is important for proportioning high slump concrete mixture at low water to cement ratios. This paper presents experimental data on the rheological property of silica colloid incorporated binder paste using naphthalene based and polycarboxylate based superplasticizer, compared to that of silica fume incorporated binder paste. Experimental data showed that silica colloid incorporated binder is compatible to tested superplasticizers in the all investigated range of silica colloid content, whereas the pastes incorporated with high silica fume content (over 10%) indicated incompatibility, especially to naphthalene based superplasticizer. There was also found out saturated content of superplasticizer corresponding to every kind of binder and water-binder ratio, with and without set retarding admixture. 


2011 ◽  
Vol 250-253 ◽  
pp. 4001-4004 ◽  
Author(s):  
Li Guo Ma ◽  
Yun Sheng Zhang

The hydration heat evolution process is studied on the pure cement paste, the cement- fly ash binary system and the cement- silica fume binary system with water binder ratio(w/b) of 0.53, 0.35 and 0.23 by using isothermal calorimeter(TAM Air). The fly ash replacement in the cement-fly ash binary system is 10%, 30% and 50% respectively. The silica fume replacement in cement-silica fume binary system is 4%, 8% and 12% respectively. The experiments results indicate that w/b had great impact on the hydration heat evolution and the hydration heat decrease with the decrease in w/b. The addition of fly ash greatly decrease the exothermic rate and total hydration heat. The addition of silica fume shortens dormant period and increases the peak exothermic rate, but reduces the total hydration heat.


2015 ◽  
Vol 820 ◽  
pp. 492-496
Author(s):  
D.C.S. Garcia ◽  
Roberto Braga Figueiredo ◽  
Maria Teresa Paulino Aguilar

The aim of this paper was to investigate the influence of heat treatment on hardness evolution of cement pastes containing silica fume. The specimens were prepared with Ordinary Portland Cement, water/binder ratio of 0,40 and 25% wt. silica fume. The specimens were cast at room temperatures and after 24 hours, they were placed in a furnace for 24 hours, with heat regimes of 100°C, 200°C and 300°C and then submitted to the ultra-microhardness test. The microstructure was analyzed using optical microscopy. The results showed that the silica fume prevents the production of calcium hydroxide and the heat treatment increases the material hardness.


2017 ◽  
Vol 149 ◽  
pp. 359-366 ◽  
Author(s):  
Jianzhong Liu ◽  
Kejin Wang ◽  
Qianqian Zhang ◽  
Fangyu Han ◽  
Jianfang Sha ◽  
...  

2011 ◽  
Vol 391-392 ◽  
pp. 161-164
Author(s):  
Tie Quan Ni ◽  
Chang Jun Ke ◽  
Li Zhang

According to the particularity of the autoclaved cement concrete that partial aggregate could participate in hydration reaction in the process of autoclaving, the optimal gradation of coarse aggregate and the optimal slurry aggregate ratio is studied, and the effect of water reducing agent for fluidity of cement paste is also studied. The optimized mix design of autoclaved cement concrete based on high strength (compressive strength and flexural strength) is done by orthogonal test with four factors (water-binder ratio, type of mineral admixture, amount and sand ratio) and four levels.


2021 ◽  
Vol 8 ◽  
Author(s):  
Xiyao Zheng ◽  
Jun Wu

One-part or “just add water” geopolymer is a cementitious material, which is friendly to environment and users in applications. However, the mechanical behavior of the soft soil stabilized by one-part geopolymer is not well acknowledged. In this study, soft clay was stabilized with ground granulated blast furnace slag (GGBFS) and fly ash (FA)-based geopolymer, which is a mixture of solid aluminosilicate precursor (Al-Si raw materials: GGBFS and FA), solid alkali activator, and water. The objective was to adopt one-part geopolymer as an alternative soil binder to completely replace ordinary Portland cement (OPC) for stabilizing the soft clay and evaluate the effect of the factors (i.e., GBFS/FA ratio in Al-Si precursor, activator/Al-Si precursor ratio, and water/binder ratio) that influenced the early strength. Results showed that the increase of the FA content in the Al-Si precursor increased the unconfined compressive strength (UCS) values significantly through the geopolymerization process. The highest UCS values were achieved with 90% GGBFS to 10% FA in the precursor when the activator/precursor and water/binder ratio is 0.15 and 0.7, respectively. The UCS values of geopolymer-stabilized clay could reach 1.5 MPa at 14 days at ambient temperature, which is much higher than that of OPC-stabilized clay. The microstructure and mineralogy analyses indicated that the prolific hydration products, such as calcium silicate hydrate (C-S-H), calcium aluminum hydrate (C-A-H), and calcium aluminum silicate hydrate (C-A-S-H), contributed greatly to strengthen the soft clay by forming the soil skeleton and infilling among clay particles, while sodium aluminosilicate (N-A-S-H) gel is only served to fill the part of porosities in the soil and cannot effectively enhance the UCS of the one-part geopolymer-stabilized soft clay. This paper results suggested that one-part GGBFS-FA–based geopolymers have the potential to replace OPC in the manufacture of stabilized soft clay.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
W. H. Cao ◽  
X. F. Wang ◽  
D. S. Zhang ◽  
X. J. Ji ◽  
X. Z. Chen ◽  
...  

A full understanding of the workability and unconfined compressive strength (UCS) of the cemented high-porosity (CHPB) material, made of surface sand, widely distributed in the western mining area, foam, and cementing materials, is important for applying in ecologically fragile mining areas of western China. In this article, the influence of solid content, density grade, sand/binder ratio, and silica fume dosage in binder on workability and strength development of CHPB samples in different curing ages is studied. Test results show that the fresh CHPB mix has good workability, due to the existence of a large number of bubbles. With the increase of density grade, the UCS of the CHPB sample increases exponentially. Workability of fresh CHPB samples significantly decreases with increasing solid content due to the reduction of interparticle distance. For a given mix proportion, the optimal solid content of CHPB samples is 83.7%. The variation of the sand/binder ratio from 3 to 4.5 results in a slight increase of workability and a significant increase of the UCS. Silica fume demonstrates improvement on workability and strength behavior, and the optimal dosage in the binder should not exceed 10%.


2000 ◽  
Vol 27 (4) ◽  
pp. 620-627 ◽  
Author(s):  
A KH Kwan

A high concrete strength can be achieved by lowering the water/binder ratio and a high workability by adding a higher dosage of superplasticizer. However, a high-performance concrete with both high strength and high workability cannot be produced by just these means because lowering the water/binder ratio leads to lower workability and there is a limit to the increase in workability that can be attained by adding superplasticizer. To produce a high-strength, high-workability concrete, the concrete strength needs to be increased without lowering the water/binder ratio. This can be done by adding condensed silica fume. In this study, a series of trial mixing aimed at developing high-strength, self-consolidating concrete (mean cube strength >80 MPa and needs no compaction for consolidation) was carried out. Several mixes suitable for making such high-performance concrete have been developed and it was found that the addition of condensed silica fume may, under favourable conditions, increase not only the strength but also the workability of the concrete mix. Based on the trial mix results, charts for the design of high-strength, high-workability concrete mixes made of the studied constituents are presented.Key words: condensed silica fume, high-strength concrete, self-consolidating concrete.


Sign in / Sign up

Export Citation Format

Share Document