Dynamic Compressive Strength of Cementitious Materials

1985 ◽  
Vol 64 ◽  
Author(s):  
L. E. Malvern ◽  
T. Tang ◽  
D. A. Jenkins ◽  
J. C. Gong
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Maximum Stress ◽  
Dynamic Range ◽  
Structural Response ◽  
Aggregate Size ◽  
Cementitious Materials ◽  
Rate Dependence ◽  
Maximum Aggregate Size ◽  
Inertia Effects

ABSTRACTFinite-element codes for structural response of reinforced concrete use as a parameter the unconfined compressive strength of the concrete, fc', which is sometimes increased by an arbitrary factor for dynamic loading. The objective of this research is to determine the rate dependence of fc' and eventually to model the rate-dependent constitutive behavior. Results of tests with a small Kolsky bar system and of a newly built larger system on concrete with a maximum aggregate size 1/2 inch are reported with strain rates at the maximum stress from 50 to 800/sec for mortar and from 5 to 120/sec for concrete. An apparent rate dependence up to almost twice the static strength is observed for both. The mortar shows an apparent linear dependence, while the high-strength concrete shows an approximately logarithmic dependence on the strain rate at the maximum stress, over the dynamic range observed. Some questions about specimen size effects and about how much of the apparent strain-rate effect is really a lateral inertia confinement effect are as yet unresolved. Continuing research is focused on observation of the lateral motion to assess lateral inertia effects in unconfined specimens and on passive confinement by steel jackets. Future efforts will be directed toward constitutive modeling.

scholarly journals Strength optimization of reactive powder concrete

2020 ◽  
Vol 13 (5) ◽  
Author(s):  
Abrahão Bernardo Rohden ◽  
Ana Paula Kirchheim ◽  
Denise Dal Molin
Keyword(s):  
Compressive Strength ◽  
Aggregate Size ◽  
Reactive Powder Concrete ◽  
Maximum Aggregate Size ◽  
Second Phase ◽  
Fine Aggregate ◽  
Inorganic Pigments ◽  
Concrete Mix Design ◽  
Fine Quartz ◽  
Reactive Powder

abstract: Recent reports on reactive powder concrete address important aspects regarding its performance. Several techniques are used to improve the design of such concretes. Ultra-high compressive strengths have been reported with the application of pre-setting pressure and autoclave curing. The objective of this work is to evaluate the use of very fine quartz powder to replace fine aggregate, nanosilica, and inorganic pigments to optimize mechanical properties of reactive powder concrete. The experimental work was developed in three distinct phases. In the first phase, mix-proportions of reactive powder concrete have been developed, considering different maximum aggregate sizes (1.2, 0.6, 0.075, and 0.045 mm). In the second phase, the influence of nanosilica on the properties of reactive powder concrete was evaluated. In the third phase, the effect of the addition of yellow, green, orange, and blue inorganic pigments to the reactive powder concrete mix-design was evaluated. Results show that the maximum aggregate size influences the compressive strength of the reactive powder concrete. A decrease from 1.2 mm to 0.045 mm in the maximum aggregate size resulted in 156 MPa increase in the compressive strength. The type of pigment did not significantly influence the compressive strength of the reactive powder concrete. The mix-proportion that resulted in the highest compressive strength (310.7 MPa) was designed using yellow pigment.

scholarly journals Meta-Analysis of Steel Fiber-Reinforced Concrete Mixtures Leads to Practical Mix Design Methodology

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3900
Author(s):  
Emilio Garcia-Taengua ◽  
Mehdi Bakhshi ◽  
Liberato Ferrara
Keyword(s):  
Design Methodology ◽  
Aggregate Size ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Data Driven ◽  
Validation Dataset ◽  
Maximum Aggregate Size ◽  
Steel Fiber Reinforced Concrete

The analysis of hundreds of SFRC mixtures compiled from papers published over the last 20 years is reported. This paper is focused on the relationships between the size and dosage of steel fibers and the relative amounts of the constituents of SFRC mixtures. Multiple linear regression is applied to the statistical modeling of such relationships, leading to four equations that show considerable accuracy and robustness in estimating SFRC mixture proportions as a function of fiber content and dimensions, maximum aggregate size, and water-to-cement ratio. The main trends described by these equations are discussed in detail. The importance of the interactions between aggregates, supplementary cementitious materials, and fibers in proportioning SFRC mixtures, as well as implications for workability and stability, are emphasized. The simplicity of these data-driven equations makes them a valuable tool to guide the proportioning of SFRC mixtures. Their predictive performance when used together as a data-driven mix design methodology is confirmed using a validation dataset.

scholarly journals Eksperimental Perbandingan Kekuatan Tekan Karakteristik Beton Self Compacting Menggunakan Agregat Kasar Alami Dan Agregat Kasar Daur Ulang

2020 ◽  
Vol 19 (1) ◽  
pp. 107-120
Author(s):  
Martinus Pramanata Sapeai ◽  
Johannes Adhijoso Tjondro
Keyword(s):  
Compressive Strength ◽  
Aggregate Size ◽  
Recycled Concrete ◽  
Mix Design ◽  
Sustainable Construction ◽  
Maximum Aggregate Size ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Coarse Aggregates ◽  
High Rise

Utilization of recycled concrete waste as an alternative to natural coarse aggregates in this experiment is in accordance with the concept of sustainable construction. Concrete is the main material of structural elements most commonly used in general construction and has properties that are difficult to recycle by themselves naturally. Nowdays concrete innovation with the concept of self compacting (SCC) is widely used especially in high rise building and buildings with special specification. SCC has high flowability properties so that it can flow and compact themselves, but in SCC with normal quality still need compactor. The concept of making test specimens is in accordance with real conditions in the field, where aggregates do not go through a cleaning process. There are four different mix design with the required specified compressive strength of 20 MPa. Mix design 1A (natural coarse) and 1B (recycled coarse aggregates) has a maximum aggregate size 12.50 mm, and mix design 2A (natural coarse) and 2B (recycled coarse aggregates) has a maximum aggregate size 19.00 mm. This experimental results in specified compressive strength concrete for mix design 1A, 1B, 2A, and 2B as follows: 30.93 MPa, 26.21 MPa, 30.82 MPa and 27.60 MPa. Therefore, recycled concrete aggregates can be alternative to natural coarse aggregates and can also be made into concrete with the SCC concept.

scholarly journals Studi Mengenai Perancangan Campuran Beton Abu Terbang dengan Pendekatan Blended Sand (Hal. 88-97)

2018 ◽  
Vol 4 (4) ◽  
pp. 88
Author(s):  
Reza Fauzi Nirwan ◽  
Priyanto Saelan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Aggregate Size ◽  
Maximum Aggregate Size ◽  
Fine Aggregate ◽  
Concrete Compressive Strength ◽  
Fly Ash Concrete ◽  
Is Research ◽  
Strength Tests ◽  
Concrete Mix

ABSTRAKPenelitian ini dilakukan untuk mengetahui hasil perancangan campuran beton abu terbang yang mensubtitusi semen dengan cara pendekatan sand blended, yaitu abu terbang yang mensubtitusi semen diperlakukan sebagai agregat halus, sehingga agregat halus merupakan campuran dari pasir dan abu terbang. Penelitian dilakukan dengan kuat tekan rencana 20 MPa dan 30 MPa. Substitusi semen oleh abu terbang sebesar  10 %, 20 %, dan 30 % dari berat semen. Ukuran maksimum agregat kasar yang digunakan adalah 20 mm, dan pasir dengan modulus kehalusan 2,768, slump rencana 6 cm dan 10 cm. Hasil pengujian tekan silinder beton berdiameter 10 cm dan tinggi 20 cm menunjukkan bahwa kuat tekan beton abu terbang yang dihasilkan berdekatan dengan beton acuan yaitu beton tanpa abu terbang, untuk semua kadar abu terbang yaitu sampai dengan kadar subtitusi semen oleh abu terbang sebesar 30 %. Pendekatan sand blended dapat dilakukan dalam perancangan campuran beton abu terbang.Kata Kunci : beton abu terbang, kuat tekan, pasir blendedABSTRACTThis is research was performed to know the result of the test of fly ash concrete mix designed by sand blended method. Fly ash will be treated as fine aggregate so that the total fine aggregate is the consist of fly ash and sand. 20 MPa and 30 MPa concrete mix are designed for 10 %, 20 % and 30 % by weight of cement subtitution by fly ash. Concrete mix use 20 mm maximum aggregate size, finess modulus of sand 2.768, and 6 cm and  10 cm slump. Compressive strength tests of 10 cm diameter and 20 cm height cylinder showed that the stength of fly ash concrete is the same as the strength of initial concrete. Fly ash concrete mix can be designed by sand blended approximation.Keywords : fly ash concrete, compressive strength, blended sand

scholarly journals The Effects of Maximum Attapulgite Aggregate Size and Steel Fibers Content on Fresh and Some Mechanical Properties of Lightweight Self Compacting Concrete

2020 ◽  
Vol 26 (5) ◽  
pp. 172-190
Author(s):  
Shubbar Jawad Al-obaidey
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Aggregate Size ◽  
Steel Fibers ◽  
Maximum Aggregate Size ◽  
Marginal Effect ◽  
Fresh Properties ◽  
Self Compacting Concrete ◽  
Flexural Tensile Strength

The main objectives of this study were investigating the effects of the maximum size of coarse Attapulgite aggregate and micro steel fiber content on fresh and some mechanical properties of steel fibers reinforced lightweight self-compacting concrete (SFLWSCC). Two series of mixes were used depending on maximum aggregate size (12.5 and 19) mm, for each series three different steel fibers content were used (0.5 %, 1%, and 1.5%). To evaluate the fresh properties, tests of slump flow, T500 mm, V funnel time, and J ring were carried out. Tests of compressive strength, splitting tensile strength, flexural tensile strength, and calculated equilibrium density were done to evaluate mechanical properties. For reference mixes, the results showed that mixes with a larger maximum aggregate size of 19 mm exhibited better fresh properties, while mechanical properties negatively affected by using a larger maximum aggregate size. The results also showed that using steel fibers led to negative effects on fresh properties, especially with higher steel fibers content and larger maximum aggregate size. The marginal effect of steel fibers on compressive strength was noticed, while for both splitting and flexural tensile strength, significant increase was obtained with increasing of steel fibers content. The properties of SFLWSCC in the fresh state had a considerable effect on mechanical properties, whereas with the best fresh properties, the best mechanical properties can be obtained.

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