Publications
Behavior of green reactive powder concrete exposed to aggressive solutions
Sep 12, 2024Journal Innovative Infrastructure Solutions
Publisher springer
DOI 10.1007/s41062-024-01666-4
Issue 9
Volume 10
Green reactive powder concrete is a new type of concrete that falls into the category of ultra-high performance concrete that contains a high proportion of cementitious materials (a considerable amount of cement replacement by waste materials), as well as fine sand, quartz powder, superplasticizers, and fibers. The major goal of this research is to study the behavior of green reactive powder concrete when exposed to aggressive solutions. In this study, the work was divided into three stages: the first stage included preparing mixes by replacing cement with waste ceramic, waste glass, and waste brick powder in different percentages and selects the optimum mix. The second stage included preparing mixes of green reactive powder concrete by replacing cement with 40% with different percentages of sand and selected the optimum two mixes. The third stage included studying the behavior of selected green reactive powder concrete when exposed to aggressive solutions (sodium chloride, magnesium chloride, magnesium sulfate, and calcium sulfate) and comparing it with normal concrete.The results covered five parts: the first indicates that the green mortar containing glass powder and brick powder gives higher values of compressive strength, density, flexural and UPV, with lower flowability than green mortar containing waste glass powder and waste ceramic powder at the same replacement ratio. Moreover, the optimum replacement that gives the highest strength is a replacement of 40% (10% waste glass powder + 30% waste brick powder). The second part indicates that the best mixes for green reactive powder concrete that give higher mechanical properties than others are green reactive powder concrete containing (1: 0.8) and (1:1.1) cement to sand with 2% micro steel fibers and 1% superlasticizer Rb1070 with 0.3% de-foamer. The third part indicates that the green mortar provides a 38.2% reduction in carbon dioxide emissions. The fourth part indicates that the compressive, flexural, indirect splitting tensile strengths, static modulus of elasticity and ultra-pulse velocity of selected green reactive powder concrete increase continuously even after exposure to aggressive solutions for 90 days in comparison to normal concrete. The rate of increases may reach up to 21%. The fifth part indicates that, by XRD analysis of selected green reactive powder concrete shows that the sharp peak and most of the peaks are quartz. In addition, the SEM morphology shows that the GRPC mixes containing nanoparticles with a large amount of calcium silicate hydrate (C-S-H) and micro-steel fibers are covered with dense cementitious matrixes with good bonding between them.Key words: Green reactive powder, ceramic, glass, brick powder, aggressive solutions, and high strength green concrete.
Influence of binary blended cement containing slag and limestone powder to produce sustainable mortar
Dec 1, 2023Journal AIP Conference Proceedings
DOI https://doi.org/10.1063/5.0171499
Issue 1
Volume 2862
Ordinary Portland Cement is among the most widely used building materials in recent years. Cement manufacturing emits one ton of CO2 per ton of Portland cement. Therefore, this led to concern about the environment’s degradation. This research investigated the effect of a binary mixture that contains limestone powder (up to 15%) and slag (up to 30%) with ordinary Portland cement, using different proportions of 20%, 25%, 30%, 35%, 40%, and 40% by replacement of cement to produce green mortar and select the best proportion. Several tests were performed, and the properties of the mortar curing at 7 and 28 days were studied for eight mixes. Tests have been conducted on flowability, flexural strength, compressive strength, dry density, ultrasonic pulse velocity, and water absorption. The test results indicate that using the binary mixture to produce green mortar when SCMs that contained limestone powder and slag were increased led to reduced flowability. Therefore, increased dosages of superplasticizers have been added to reduce water demand. The results showed that replacing (30%) of OPC with (10% limestone and 20% slag) in the presence certain dosage of superplasticizer, gave the higher compressive strength and flexural strength among other mixes
Characteristics of self-compacting green concrete
Sep 30, 2023Journal Discover Civil Engineering
Publisher springer
DOI 10.1007/s44290-024-00083-x
Issue 1
Volume 1
Locally, conventional concrete is still created utilizing river sand and crushed stone as filer materials. The massive quarry dust by-product remain untapped in the production of concrete. The coal-fired power station produce significant quantities of Type F fly ash. Self-compacting concrete (SCC) provides many advantages for creating high-quality concrete. Consequently, the main objective of this research is to create a mix design for high-strength SCC utilizing a binary blends, hybrid fibers and fine aggregates that meet both hardened and fresh concrete characteristics. The study is conducted in amendment of w/b ratio, superplasticizer, proportion of fine aggregate to coarse aggregate, optimumal cement replacing by fly ash, dosage of low macro fibre and micro fibre. Mix-50c-X is the best mix design that was produced. The mix quantity for 1m3 concrete was 315 kg Class F fly ash, 315 kg OPC, 630 kg quarry dust, 508 kg river sand, 400 kg coarse aggregate, 0.7% superplasticizer,0.32% w/b, 0.10% macro fiber, and 0.01% micro fiber. This SCC mixture showed fresh characteristics as well as compressive strengths of more than 22 MPa and 62 MPa after 1 day and 28 days, respectively. The results of high-strength SCC demonstrated the enormous potential for the local construction, especially precast product
Limestone powder, calcined clay and slag as quaternary blended cement used for green concrete production
Aug 1, 2023Journal Journal of Building Engineering
Publisher Elsevier
DOI 10.1016/j.jobe.2023.107644
Issue 107644
Volume 79
Cement is among the most widely used building materials in recent years. In addition, the accumulation of massive waste has impacted the city's appearance. As a result, there was a need to reduce waste by using by-products from industrial waste to replace cement and reduce greenhouse emissions to produce mortar or concrete green that has good performance, environmentally and sustainably. This research study aims to design green concrete with the highest feasible replacement level with different cement content that satisfies fresh and mechanical characteristics used for structural application and eliminate negative environmental impacts simultaneously. The empirical work was conducted by preparing 12 blends to produce green concrete by substituting cement with three ratios of various by 30% (10% LMP +10% SS + 10% CC), 40% (10% LMP +10% SS + 20% CC), and 50%(10% LMP +15% SS + 25% CC) with three binder contents (355 kg/m3, 400 kg/m3, and 460 kg/m3). The mix design was carried out according to the American Concrete Institute (ACI) Code. Then environmental influences of green concrete blends were calculated by evaluating the declines in carbon dioxide (CO2) emissions. The results showed that adding limestone powder (LMP),calcined clay (CC), and steel slag (SS) as partial cement replacement decreased the slump properties of fresh concrete, so an increased dosage of superplasticizer (SP) in the fresh properties is needed. Green concrete containing quaternary cement by 30%, 40%, and 50% with SP dosage certain gave higher compressive, flexural, and splitting strength values at 90 days compared to normal concrete. However, UPV values indicate that all green concrete is of suitable quality. While water absorption has slightly increased in quaternary cement containing 50% for binder content 355, 400, and 460 kg/m3 increased by 4.2%, 2.7%, and 2.1%, respectively, compared with plain concrete. The evaluated reduction of carbon dioxide emissions study indicated that the green concrete, when increased in cement replacement percentages by up to 50% for binder content 355, 400, and 460 kg/m3 reduced CO2 emissions by 35.9%, 36.4%, and 37.1%, respectively. As a result, adopting the idea of green concrete is a promising strategy for reducing carbon dioxide emissions and conserving natural resources.
PROPERTIES EVALUATION OF GREEN MORTAR CONTAINING WASTE MATERIALS
May 12, 2023Journal ASEAN Engineering Journal
Publisher Elsevier
DOI 10.11113/aej.v13.18986
Issue 13
Volume 2
The accumulation of massive waste has impacted human health and the city's appearance. As a result, there was a need to reduce waste by using by-products from industrial waste to replace cement, such as limestone, fly ash, silica fume, steel slag, and other minerals known as supplementary cementitious materials are produced environmentally and sustainably. This paper's purpose is to design a green mortar with the highest possible replacement of cement that has acceptable fresh and hardened characteristics. In this paper, three (SCMs), such as limestone powder (10%), calcined clay (0–35%), and slag (0–30%), were used to prepare ternary mixtures. The materials used in this research are available locally in Mosul, Iraq. The experimental studies were carried out for twelve mixes. The tests of flowability, flexural strength, compressive strength, dry density, ultrasonic pulse velocity, and water absorption on green mortar have been conducted. The cement was replaced 30% to 60% with a combination of ternary cement containing calcined clay, limestone, and slag in different replacement percentages than in other green mortar mixes. The results found that replacing OPC (30%), which contains 10% limestone, 10% steel slag, and 10% calcined clay, gives the highest compressive strength and flexure strength enhancement, which are 24% and 18% greater than the plain mortar after 28 days. When cement replacement was increased for ternary mixes, the result differed slightly from the plain mortar. Water absorption increased as the SCMs were increased. Dry density showed little effect.