ACI Global Home Middle East Region Portal Western Europe Region Portal
Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Topics In Concrete
Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 393 Abstracts search results
Document:
SP364_01
Date:
December 1, 2024
Author(s):
Deuckhang Lee, Hyo-Eun Joo, Sun-Jin Han, Jae Hyun Kim, and Kang Su Kim
Publication:
Symposium Papers
Volume:
364
Abstract:
In current ACI 318 code, crack control design criterion for prestressed concrete (PSC) members is stricter than conventional reinforced concrete (RC) members. In particular, it is stipulated that the net tensile stress of prestressing strands should be controlled under 250 MPa (36.3 ksi) in the serviceability design of PSC members belonging to the Class C section that is expected to be cracked under service load conditions. To this end, the nonlinear cracked section analysis is essentially required to estimate the tensile stress of the prestressing strands under the service loads, which requires cumbersome iterative calculations in practice. This study aims to propose a simplified method to estimate the net tensile stress of the prestressing strands (Δfps) under the service load conditions and also a tabulated checking method whether the net tensile stress (Δfps) exceeds the stress limit with respect to the magnitude of effective prestress (Δfse). Finally, applicability of 2,400 MPa (348 ksi) Grade strands is also experimentally investigated.
DOI:
10.14359/51745453
CI4609Kanavaris
September 1, 2024
Fragkoulis Kanavaris, Matthew Munro, and Luca Montanari
Concrete International
46
Issue:
9
As the concrete, cement, and wider construction industries around the world move toward net-zero emissions, many alternative concrete and cement technologies have emerged with the intention of reducing the embodied carbon (EC) of concrete. Concretes have been labeled as “sustainable” and “low carbon,” and such terms have been used inconsistently. This article introduces an EC classification system.
SP-362_76
June 18, 2024
Wena de Nazaré do Rosario Martel, Josée Duchesne, and Benoît Fournier
362
Due to its predominant soda-lime composition, most post-consumer glass processed by recycling facilities would be classified as high-alkali pozzolanic glass powder (GP). In cementitious matrices, the intrinsic alkaline pore solution induces the dissolution of both silica and alkali ions. Therefore, the GP can potentially induce two similar reactions in concrete: either a deleterious alkali-silica reaction or a pozzolanic reaction. The equilibrium of the pore solution will determine which reaction will prevail in the long term. To understand the chemical stability of GP in a cementitious system, the evolution of the solubility of key elements in an alkali-rich synthetic pore solution was studied as a function of reaction time, particle size, presence of Ca(OH)b>2b> and CaCOb>3b>, and binder/solution ratio (B/S). The solution was based on the R³ method, which consists mainly of lab-grade chemicals such as KOH and Kb>2b>SOb>4b>. Although the chemical equilibrium seems to be fully reached in the first hours of hydration, the main products, such as C-S-H, are unstable because the alkali leaching/uptake in the C-S-H chains is dynamically evolving. The experiments show that both C-S-H precipitation and alkali leaching rates increase with increasing B/S ratio and decreasing particle size, and are directly related to the presence of calcium in the solution.
10.14359/51742026
SP-362_70
Nader Ghafoori, Ariful Hasnat, and Aderemi Gbadamosi
This paper examines the influence of harvested fly ash on the properties of mortar and concrete. Class F and harvested fly ash were used at the substitution rate of 20% by weight of Portland cement. The investigated properties included heat release, consistency, setting time, compressive strength at different testing ages, absorption, the volume of permeable voids, surface resistivity, and drying shrinkage. The results revealed that the harvested fly ash produced the lowest released heat of hydration and longest setting times. Mixtures containing harvested fly ash displayed lower strength at all curing ages. Compared to traditional fly ash, harvested fly ash showed inferior transport properties for both absorption rate, permeable voids, and surface resistivity. Mixtures containing harvested fly ash showed comparable 120-day drying shrinkage when compared with the companion mortars made with traditional fly ash.
10.14359/51742020
SP-362_44
June 14, 2024
Dena Shalaby, Émilie Garneau, Mathieu Fiset, Joao Augusto Lago Araujo Seixas, Ahmed Rahem
The Production of Portland cement used in concrete and the large amount of industrial waste generated worldwide represent critical environmental and economic issues. The reuse of bauxite residue generated during alumina production by Bayer’s process to replace Portland cement and produce sustainable and environmentally friendly geopolymer concrete is a promising solution. This paper presents the development and characterization of bauxite residue and class F fly ash-based geopolymer mortar and concrete. The parameters studied for the mixture proportions are the bauxite residue to class F fly ash ratio, the water-to-binder ratio, and the curing condition, in terms of duration and temperature. Then, the compressive strength of the geopolymer mortar and concrete is characterized with experimental tests. Results show that, with appropriate mixture proportions and curing conditions, a large amount of bauxite residue (up to 70%) can be used to replace fly ash and obtain geopolymer concrete with improved quality characteristics that meet the construction field’s sustainable development criteria.
10.14359/51741013
Results Per Page 5 10 15 20 25 50 100
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Edit Module Settings to define Page Content Reviewer