scholarly journals Concrete manufactured with crushed asphalt as partial replacement of natural aggregates

2016 ◽  
Vol 66 (324) ◽  
pp. 101 ◽  
Author(s):  
L. Coppola ◽  
P. Kara ◽  
S. Lorenzi
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Drying Shrinkage ◽  
Experimental Results ◽  
Recycled Aggregate ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Negative Effect ◽  
Natural Aggregates ◽  
Positive Effect

The paper focuses on the reuse of crushed asphalt (GA) as a partial replacement (up to 20%) of natural aggregates for concrete manufacture. Addition of GA aggregates produced a positive effect on workability loss. The GA mixes, however, showed a significant tendency to bleed and segregate at the highest replacement percentage applied. GA led to a decrease of compressive strength in concrete (with respect to that of the reference concrete) up to 50% due to the weakness of the cement paste / recycled aggregate interface. To compensate for this negative effect, a reduction of w/c for the GA concretes was necessary. A decrease of w/c allowed the GA concretes to show drying shrinkage values substantially similar to those of reference concrete with the same cement factor. The experimental results confirmed the possibility of partial substitution (max. 15%) of natural aggregates with crushed asphalt for making concrete.

Drying Shrinkage of Fly Ash Mortar Mixed with Seawater

2015 ◽  
Vol 802 ◽  
pp. 118-123 ◽  
Author(s):  
John Wilmer Bautista ◽  
John Benedict Crockett ◽  
Beatrice Ann Liu ◽  
Timothy John Obra ◽  
Cheryl Lyne Roxas
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Fly Ash ◽  
Carbon Dioxide Emissions ◽  
Drying Shrinkage ◽  
Water Shortage ◽  
Ash Content ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Micro Cracks

Drying shrinkage in mortar produces cracks and micro-cracks which affect the durability of a structure. The effects of seawater as a substitute to freshwater and fly ash as a partial replacement for cement were investigated in this study in order to address the predicted water shortage by 2025 and the increasing carbon footprint from carbon dioxide emissions worldwide. Moreover, these materials are also more economical alternatives to freshwater and cement. Rectangular prism specimens with varying fly ash content (10%, 15%, 20%, 25%, and 30%) were cast to measure the drying shrinkage in mortar while 50-mm cube mortar specimens were prepared to determine the compressive strength. This study investigated whether the addition of fly ash and seawater reduced the drying shrinkage of mortar. From the results, it was found that mortar specimens with 20% fly ash replacement achieved the highest early and late strengths. Partial substitution of fly ash would result to shrinkage in mortar while substitution of seawater to freshwater counteracts the effects of fly ash, thus producing less shrinkage. Fly ash content between 20%-25% combined with seawater produces the least shrinkage value without compromising the minimum required compressive strength.

THE USE OF QUARRY DUST FOR PARTIAL REPLACEMENT OF CEMENT IN CEMENT-SAND MORTAR

2021 ◽  
Vol 4 (4) ◽  
pp. 432-437
Author(s):  
Muhammad Magana Aliyu ◽  
Muhammad Musa Nuruddeen ◽  
Yahaya Atika Nura
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Cement Paste ◽  
Dust Content ◽  
Experimental Results ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Cement Replacement ◽  
Setting Times ◽  
Quarry Dust

This research was carried out to investigate the effect of partially replacing cement with quarry dust in cement-sand mortar. Tests including setting times, water absorption, compressive strength and density test were carried out on mortar with cement partially replaced with 0%, 5%, 10%, 15%, 20%, 25% and 30% quarry dust and presented. Experimental results show that replacement of quarry dust as partial replacement of cement in cement-sand mortar decrease the initial and final setting times of cement paste and increase the water absorption of the mortar. The partial replacement shows an improvement of compressive strength at 5% quarry dust content after which there is a decrease with increase in quarry dust content at all the ages. The increase in compressive strength at 5% indicates possible pozzalanic activity at that level. Thus quarry dust can be utilized as cement replacement material at 5% dust content. Above this it can be utilized as fine aggregate replacement for use in low-strength mortar applications

scholarly journals Study of the Compressive Strength of Concrete with Partial Replacement of Recycled Coarse Aggregates

2021 ◽  
Vol 11 (3) ◽  
pp. 7191-7194
Author(s):  
X. H. Vu ◽  
T. C. Vo ◽  
V. T. Phan
Keyword(s):  
Compressive Strength ◽  
Recycled Aggregate ◽  
Concrete Mixture ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Replacement Rate ◽  
Coarse Aggregates ◽  
Compressive Strength Of Concrete ◽  
Natural Aggregates

This paper presents a study on the compressive strength of concrete using recycled aggregates. The concrete was designed to have a 25MPa compressive strength and an 8cm slump. The rates of replacing natural aggregates with recycled coarse were 0%, 10%, and 20%. The test samples were compressed to determine their compressive strength value after 7, 14, and 28 days of curing. The results showed that the concrete slump did not change effectively at a 10% replacement rate. When using 20% recycled aggregates, the concrete was too hard and the homogeneity of the concrete mixture could not be guaranteed. The compressive strength slightly decreased using 10% of recycled aggregates and decreased significantly using 20%. Therefore, 20% of recycled aggregate replacement is not suitable. The results showed that using recycled aggregates at a rate of 10% is optimal.

scholarly journals IMPACT OF USING RECYCLED AGGREGATES ON COMPRESSIVE STRENGTH OF CONCRETE

2019 ◽  
pp. 134-137
Author(s):  
Khaoula Naouaoui ◽  
Azzeddine Bouyahyaoui ◽  
Toufik Cherradi
Keyword(s):  
Compressive Strength ◽  
Experimental Studies ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Aggregate Concrete ◽  
Natural Aggregates ◽  
Compressive Resistance

Recycled aggregate concrete is considered the next generation in the field of construction: it respects the environment, solves the problem of debris management and is economically profitable. In order to better adapt its use, technical studies, experimental studies and simulations are carried out in all research centers around the world in order to define its field of application. Our study falls within this framework. It is concerned with the study of the mechanical characteristics of recycled aggregate concrete essentially the compression test for various percentages of replacement. The purpose of this study is to confirm the results of studies by other researchers and to find techniques that will maximize the replacement of natural aggregates with recycled aggregates. The concrete chosen for these tests is an old building in the region of Rabat, Morocco which has been built more than 40 years and demolished in the year of 2017. The tests carried out showed a decrease in the compressive resistance noted when the replacement rates exceed 50% rate. The first improvement methods were put in place and being tested: the partial replacement of cement with pozzolan (20% rate) known by his improving of the compressive strength for ordinary concrete, the partial replacement of the large proportion [12.5-31.5] only in recycled concrete and work with natural gravels. Other improvements will be proposed as the studies progress.

scholarly journals Design of Concrete Made with Recycled Brick Waste and Its Environmental Performance

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 463
Author(s):  
Ivan Janotka ◽  
Pavel Martauz ◽  
Michal Bačuvčík
Keyword(s):  
Building Materials ◽  
Research Process ◽  
Added Value ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Type Ii ◽  
Natural Clays ◽  
Natural Aggregates ◽  
Standardized Parameters

In addition to the known uses of natural clays, less publication attention has been paid to clays returned to the production process. Industrially recovered natural clays such as bricks, tiles, sanitary ceramics, ceramic roofing tiles, etc., are applicable in building materials based on concrete as an artificial recycled aggregate or as a pozzolanic type II addition. In this way, the building products with higher added value are obtained from the originally landfilled waste. This paper details the research process of introducing concrete with recycled brick waste (RBW) up to the application output. The emphasis is placed on using a RBW brash as a partial replacement for natural aggregates and evaluating an RBW powder as a type II addition for use in concrete. A set of the results for an RBW is reported by the following: (a) an artificial RBW fine aggregate meets the required standardized parameters for use in industrially made concrete, (b) a RBW powder is suitable for use in concrete as industrially made type II addition TERRAMENT showing the same pozzolanic reactivity as a well-known and broadly used pozzolan-fly ash, and (c) such an RBW as aggregate and as powder are, therefore, suitable for the production of industrially made TRITECH Eco-designed ready-mixed concrete.

scholarly journals Effect of Waste Clay Brick Powder on Physical and Mechanical Properties of Cement Paste

2021 ◽  
Vol 15 (1) ◽  
pp. 370-380
Author(s):  
David Sinkhonde ◽  
Richard Ocharo Onchiri ◽  
Walter Odhiambo Oyawa ◽  
John Nyiro Mwero
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Partial Replacement ◽  
Clay Brick ◽  
X Ray ◽  
Cement Replacement ◽  
Clay Bricks ◽  
Brick Powder ◽  
Scanning Electron

Background: Investigations on the use of waste clay brick powder in concrete have been extensively conducted, but the analysis of waste clay brick powder effects on cement paste is limited. Materials and Methods: This paper discusses the effects of waste clay brick powder on cement paste. Fragmented clay bricks were grounded in the laboratory using a ball mill and incorporated into cementitious mixes as partial replacement of Ordinary Portland Cement. Workability, consistency, setting time, density and compressive strength properties of paste mixes were investigated to better understand the impact of waste clay brick powder on the cementitious paste. Four cement replacement levels of 2.5%, 5%, 7.5% and 10% were evaluated in comparison with the control paste. The chemical and mineral compositions were evaluated using X-Ray Fluorescence and X-Ray Diffractometer, respectively. The morphology of cement and waste clay brick powder was examined using a scanning electron microscope. Results: The investigation of workability exhibited a reduction of slump attributed to the significant addition of waste clay brick powder into the cementitious mixes, and it was concluded that waste clay brick powder did not significantly influence the density of the mixes. In comparison with the control paste, increased values of consistency and setting time of cement paste containing waste clay brick powder confirmed the information available in the literature. Conclusion: Although waste clay brick powder decreased the compressive strength of cement paste, 5% partial cement replacement with waste clay brick powder was established as an optimum percentage for specimens containing waste clay brick powder following curing periods of 7 and 28 days. Findings of chemical composition, mineral composition and scanning electron microscopy of waste clay brick powder demonstrated that when finely ground, fragmented clay bricks can be used in concrete as a pozzolanic material.

High Volume Slag and Slag-Fly Ash Blended Cement Pastes Containing Nano Silica

2019 ◽  
Vol 967 ◽  
pp. 205-213
Author(s):  
Faiz U.A. Shaikh ◽  
Anwar Hosan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Paste ◽  
Ordinary Portland Cement ◽  
Blended Cement ◽  
High Volume ◽  
Ash Content ◽  
Partial Replacement ◽  
Nano Silica ◽  
Cement Pastes

This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO2 emission.

Incorporation of glass powder and metakaolin as cement partial replacement to improve concrete mechanical properties and increase service life

2020 ◽  
Vol 54 (21) ◽  
pp. 2965-2983
Author(s):  
Guilherme Cunha Guignone ◽  
Geilma Lima Vieira ◽  
Robson Zulcão ◽  
Maxwell Klein Degen ◽  
Sérgio Hémerson de Moraes Mittri ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Service Life ◽  
Glass Powder ◽  
Colorimetric Method ◽  
Point Of View ◽  
Ternary Mixtures ◽  
Chloride Diffusion ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Chloride Permeability

The search for the application of alternative materials, that can partially replace cement and increase the service life of concrete structures, is necessary from the environmental and technological point of view. In this context, the partial substitution of cement in concretes by pozzolanic additions can be performed as ternary mixtures, such as the combined incorporation of glass powder and metakaolin, enabling the reduction of cement consumption and the minimisation of the CO2 emissions and the natural resources consumption. Therefore, this research evaluated the incorporation of glass powder and metakaolin in an isolated and combined way, as partial substitutes for cement in concretes. The compressive strength and the chloride penetration resistance were evaluated by means of electrical resistivity, chloride permeability, steady-state chloride migration test and chloride diffusion test, obtaining the diffusivity and chloride contaminated depth by the colorimetric method. The alkali–silica reactivity test was also conducted, because of the alkali content of the waste glass being higher than the standard requirements. It was concluded that the combined use of ground glass powder and metakaolin in concrete allowed the replacement of up to 20% of the cement, promoting microstructural improvements and increasing properties related to durability and compressive strength already available at 28 days. Furthermore, it increased the estimated service life up to five times, working as an alternative for the reduction of cement use and concrete properties' improvement.

scholarly journals Effect of basalt powder addition on properties of mortar

2019 ◽  
Vol 262 ◽  
pp. 06002 ◽  
Author(s):  
Magdalena Dobiszewska ◽  
Waldemar Pichór ◽  
Paulina Szołdra
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Beneficial Effect ◽  
Cement Paste ◽  
Cement Hydration ◽  
Asphalt Mixture ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Freeze Resistance ◽  
Powder Addition

The study evaluates the use of waste basalt powder as a replacement of cement to enhance hydration of cement and mortar properties. The basalt powder is a waste resulting from preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in adding the powder waste as a partial replacement of cement. The percentages of basalt powder in this research are 0-40% and 0-20% by mass of cement in the pastes and mortars respectively. The experiments were carried out to determine the influence of basalt powder on cement hydration, as well as compressive and flexural strength. Results indicate that addition of basalt powder as a replacement of cement leads to deterioration of compressive strength. The flexural strength of mortar is improved in some cases. Waste basalt powder only slightly influences the cement hydration.

Effects of Water Absorption and Size of Superabsorbent Polymers on Internal Curing of Cement Paste

2013 ◽  
Vol 743-744 ◽  
pp. 193-197 ◽  
Author(s):  
Wen Bin Wang ◽  
Ji Ping Liu ◽  
Qian Tian ◽  
Yu Jiang Wang ◽  
Lei Li
Keyword(s):  
Water Absorption ◽  
Cement Paste ◽  
Autogenous Shrinkage ◽  
High Water ◽  
Internal Curing ◽  
Superabsorbent Polymers ◽  
Large Size ◽  
Negative Effect ◽  
The Relationship ◽  
Positive Effect

In recent years, superabsorbent polymers (SAPs) are considered as promising material for internal curing of cement-based materials, however, the relationship between SAPs structure and its performance are still unclear. In this paper, SAPs with different water absorption and size were selected to discuss their effect on autogenous deformation of cement paste and strength of mortars. Results indicated that SAPs with large-size and high-water absorption had positive effect on autogenous shrinkage reduction. The influence of SAPs on mortar mechanical properties revealed that SPAs seemed to have no negative effect on the strength of cement past. The increase of the strength might be from the decreased water/cement (w/c) ratio due to the water absorption by SAPs.

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