The Experimental Study of Early-Age Strength and Elastic Modulus of Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1192-1197 ◽  
Author(s):  
Deng Xiang Zhang ◽  
Wei Jun Yang

Based on large numbers of experiment results, this paper carries out statistical analysis and proposes the probability distribution properties of the random process of strength and elastic modulus and their coefficient of variation, and develops a new prediction model of early-age strength and elastic modulus and their coefficient of variation respectively. The model can provide good prediction of the development of mechanical properties of concrete structures in aging, and it is important to evaluate the concrete structure safety and reliability in the construction period.

2011 ◽  
Vol 90-93 ◽  
pp. 2188-2192
Author(s):  
Nan Xie ◽  
Jie Ouyang ◽  
Bing Li ◽  
Jing Hui Lu

Abstract. The compressive strength and elastic modulus of early-age shotcrete have important influence on the safety of tunnel during construction period. In order to investigate the laws of the mechanical properties of early-age shotcrete, experiments on the compressive strength and elastic modulus of early-age shotcrete with two different mixes used frequently on construction sites were carried out. The results show that the compressive strength and elastic modulus of shotcrete develop fairly rapidly and especially the development of elastic modulus of shotcrete is faster than that of ordinary concrete. There is an exponential relationship between the compressive strength and time as well as the elastic modulus development and time. Simultaneously their formulas were derived. The research results of this paper are not only helpful to understand the laws of the mechanical properties of early-age shotcrete, but also provide some reference for the reliability analysis of tunnel under construction.


Author(s):  
Sivamani Jagan ◽  
Thurvas Renganathan Neelakantan ◽  
Palaniraj Saravanakumar

Extensive studies have been performed on the mechanical and durability properties of the concrete prepared with recycled coarse aggregates (RCA), however, only modest consideration has been given to the studies on the behaviour of RAC prepared by alternative mixing approach techniques. This study presents the mechanical properties of the recycled aggregate concrete (RAC) with different percentages of RCA prepared by normal mixing approach (NMA), two-stage mixing approach (TSMA) and sand enveloped mixing approach (SEMA) techniques. The manufactured concrete mixtures were tested for compression, tension, flexure and elastic modulus at 7, 28 and 90 days. The results indicate that the mechanical properties of the RAC (with 100% of RCA) prepared through TSMA and SEMA were improved by 9.36 and 12.14% at 28 days. Perhaps, prolonged curing to TSMA and SEMA mixtures improved the mechanical properties of the RAC that is nearly equal to normal aggregate concrete (NAC) prepared by NMA.


2012 ◽  
Vol 238 ◽  
pp. 161-164 ◽  
Author(s):  
Qing Long Wang ◽  
Jun Chao Bao

A designed experimental study has been conducted to investigate the effect of silica fume on mechanical properties and carbonation resistance of concrete, a large number of experiments have been carried out in this study. The results indicate that the addition of silica fume has improved the compression strength and elastic modulus of concrete. A considerable increase for the compression strength and elastic modulus of the concrete was observed by increasing the dosage of silica fume. Besides, the addition of silica fume can improve the carbonation resistance of the concrete composite evidently, and the carbonation resistance is becoming better and better as the silica fume content is increasing gradually.


2019 ◽  
Vol 275 ◽  
pp. 01026
Author(s):  
Chenjie Zhao ◽  
Xiaohong Xiong ◽  
Zhenhua Xiong ◽  
Kangwen Wu ◽  
Zhen Cao ◽  
...  

Six specimens were made and tested to study the mechanical properties of LBL beams. The mean ultimate loading value is 68.39 MPa with a standard deviation of 6.37 MPa, giving a characteristic strength (expected to be exceeded by 95% of specimens) of 57.91 MPa, and the mean ultimate deflection is 53.3 mm with a standard deviation of 5.5 mm, giving the characteristic elastic modulus of 44.3 mm. The mean ultimate bending moment is 20.18 kN.m with a standard deviation of 1.88 kN.m, giving the characteristic elastic modulus of 17.08 kN.m. The mean elastic modulus is 9688 MPa with a standard deviation of 1765 MPa, giving the characteristic elastic modulus of 6785 MPa, and the mean modulus of rupture is 93.3 MPa with a standard deviation of 8.6 MPa, giving the characteristic elastic modulus of 79.2 MPa. The strain across the cross-section for all LBL beams is basically linear throughout the loading process, following standard beam theory.


2011 ◽  
Vol 409 ◽  
pp. 544-549 ◽  
Author(s):  
Luca Sorelli ◽  
Daniel Vallée ◽  
Aali R. Alizadeh ◽  
James Beaudoin ◽  
Nicholas Randall

In order to reduce CO2emissions, the cement industry has developed a new class cements. The Calcium-Silicate-Hydrates (CSH) that form are generally characterized by a low stoichiometric ratio for CaO and SiO2. This low C/S ratio affects the C-S-H layer structure and has a significant effect on the mechanical properties. This work exploits a novel statistical nanoindentation technique (SNT) to study the effect of the C/S ratio on the mechanical properties of synthetic CSH. Different CSH types were prepared by varying the C/S ratio of the starting materials. After undertaking a grid nanoindentation approach for each sample, the statistical analysis allowed extracting the mechanical properties, such as elastic modulus, hardness and creep. The results of this preliminary work shed new light on the implications of C-S-H stoichiometry on mechanical properties.


Author(s):  
Medard Makrenek

The paper presents the methodology behind the statistical selection of input parameters using the example of spraying two cold-sprayed coatings. The Ti and Cr3C2-25(Ni20Cr)-Gr coatings were tested. Despite the large difference in the structure of these coatings, nanoindentation studies were carried out focusing on the nano hardness H and elastic modulus E. Based on the four input parameters and two output parameters, a 2-level factorial 2(k-p) experimental design was performed. The conducted analysis showed the significant influence of the spray distance on the H and E values in the case of the Ti coating. The input parameters of the spray distance and the type of carrier gas used turned out to be statistically significant in the case of the cermet coating. Taking into account the statistical analysis, the coatings were sprayed with modified values of the input parameters.


2012 ◽  
Vol 166-169 ◽  
pp. 3323-3328
Author(s):  
Ling Jun Xie ◽  
Ai Liang Zhai ◽  
Chun He Wang ◽  
Chang Liang Ji ◽  
Shu Jian Chen

By experimental, study on the elastic modulus including the failure modes of Recycled Concrete made of Brick and Tile with the splitting tensile strength and the compressive strength, And the relational formula between the splitting tensile strength and the compressive strength was summarized from the results.


Sign in / Sign up

Export Citation Format

Share Document