scholarly journals Various Hydration Reactions of Silica Fume Blended Cement under Different Curing Conditions, and a Hypothesis for the Ultra High Strength Development Mechanism of RPC

2006 ◽  
Vol 55 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Masami UZAWA ◽  
Yoshihide SHIMOYAMA ◽  
Shigeo KOSHIKAWA
Keyword(s):  
Silica Fume ◽  
Blended Cement ◽  
High Strength ◽  
Strength Development ◽  
Curing Conditions ◽  
Development Mechanism

scholarly journals Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Jae-Sung Mun ◽  
Myung-Sug Cho
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Relative Strength ◽  
Curing Temperature ◽  
Strength Development ◽  
Curing Conditions ◽  
Strength Concrete ◽  
Equivalent Age ◽  
Compressive Strength Development

This study examined the relative strength-maturity relationship of high-strength concrete (HSC) specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1) isothermal curing conditions of 5°C, 20°C, and 40°C and (2) terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

Experimental analysis of behaviour of light weight high performance concrete with crystallized slag

2016 ◽  
Vol 13 (5) ◽  
pp. 447-452 ◽  
Author(s):  
Sabah Ben Messaoud ◽  
Bouzidi Mezghiche
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Mix Design ◽  
Strength Development ◽  
Hardened Concrete ◽  
Natural Pozzolan ◽  
Content Type

Purpose The aim of this paper is to make lightweight high-performance concrete (LWHPC) with high economic performance from existing materials on the Algerian market. Concrete with high values with regard to following properties: mechanical, physical, rheological and durability. Because of the implementation of some basic scientific principles on the technology of LWHPC, this study is part of the valuation of local materials to manufacture LWHPC with several enhanced features such as mechanical, physical chemical, rheological and durability in the first place and with regard to the economic aspect in the second place. Design/methodology/approach The experimental study focused on the compatibility of cement/superplasticizer, the effect of water/cement ratio (W/C 0.22, 0.25, 0.30), the effect of replacing a part of cement by silica fume (8 per cent), the effect of combined replacement of a part of cement by silica fume (8 per cent) and natural pozzolan (10 per cent, 15 per cent, 25 per cent) and the effect of fraction of aggregate on properties of fresh and hardened concrete using the mix design method of the University of Sherbrooke, which is easy to realize and gives good results. Findings The results obtained allow to conclude that it is possible to manufacture LWHPC with good mechanical and physical properties in the authors’ town with available materials on the Algerian market. The mix design and manufacture of concrete with a compressive strength at 28 days reaching 56 MPa or more than 72 MPa is now possible in Biskra (Algeria), and it must no longer be used only in the experimental field. The addition of silica fume in concrete showed good strength development between the ages of 7 and 28 days depending on the mix design; concrete containing 8 per cent silica fume with a W/B (water/binder) of 0.25 has a compressive strength higher than other concretes, and concrete with silica fume is stronger than concrete without silica fume, so we can have concrete with a compressive strength of 62 MPa for W/C of 0.25 without silica fume. Then, one can avoid the use of silica fume to a resistance of concrete to the compressive strength of 62 MPa and a slump of 21 cm, as silica fume is the most expensive ingredient in the composition of the concrete and is very important economically. A main factor in producing high-strength concrete above 72 MPa is to use less reactive natural pozzolan (such as silica fume) in combination with silica fume and a W/B low of 0.25 and 0.30. The combination of silica fume and natural pozzolan in mixtures resulted in a very dense microstructure and low porosity and produced an enhanced permeability of concrete of high strength, as with resistance to the penetration of aggressive agents; thus, an economical concrete was obtained using this combination. Research limitations/implications The study of the influence of cementitious materials on concrete strength gain was carried out. Other features of LWHPC such as creep, cracking, shrinkage, resistance to sulphate attack, corrosion resistance, fire resistance and durability should be also studied, because there are cases where another feature is most important for the designer or owner than the compressive strength at 28 days. Further studies should include a range of variables to change mixtures significantly and determine defined applications of LWHPC to produce more efficient and economical concretes. It is important to gather information on LWHPC to push forward the formulation of characteristics for pozzolan concrete for the building industry. Practical implications The LWHPC can be used to obtain high modules of elasticity and high durability in special structures such as marine structures, superstructures, parking, areas for aircraft/airplane runways, bridges, tunnels and industrial buildings (nuclear power stations). Originality/value The novel finding of the paper is the use of crystallized slag aggregates and natural pozzolan aggregates to obtain LWHPC.

scholarly journals Influence of Different Drying Conditions on High Strength Concrete Compressive Strength

10.14311/228 ◽  
2001 ◽  
Vol 41 (3) ◽  
Author(s):  
M. Safan ◽  
A. Kohoutková
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Development ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Development Rates ◽  
Drying Conditions

The influence of different drying conditions on the compressive strength and strength development rates of high strength concrete up to an age of 28 days was evaluated. Two HSC mixes with and without silica fume addition were used to cast cubes of 10 cm size. The cubes were stored in different drying conditions until the age of testing at 3, 7, 28 days.

Characterisation of High Calcium Wood Ash for Use as a Constituent in Wood Ash-Silica Fume Ternary Blended Cement

2011 ◽  
Vol 346 ◽  
pp. 3-11 ◽  
Author(s):  
Cheah Chee Ban ◽  
Ramli Mahyuddin
Keyword(s):  
Silica Fume ◽  
Blended Cement ◽  
High Strength ◽  
Strength Properties ◽  
Wood Ash ◽  
Biomass Energy ◽  
Cement Replacement ◽  
Constituent Material ◽  
High Calcium ◽  
Partial Cement Replacement

The potential stabilization of high calcium wood waste ash (HCWWA) derived from the wood biomass energy production for use as cementitious material using another industrial by-product, silica fume, was investigated. Throughout the study, both HCWWA and DSF were characterized in term of their respective chemical composition and mineralogical phases. Besides, physical characteristics of HCWWA and DSF in terms of particle grading and specific surface area were established in order to evaluate their suitability as for use as constituent material in blended cement. Additionally, compressive strength properties of high strength mortar produced using HCWWA and DSF blended cement were investigated. Results indicated that the use of HCWWA as a partial cement replacement did not have significant adverse effect on the workability of fresh mortar. The enhancement of the compressive of mortar was observed for mortar mixes containing DSF and HCWWA levels of cement replacement up to 16%.

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