Mechanical strength, durability and drying shrinkage of structural mortar containing HCWA as partial replacement of cement

Cement emulsified asphalt (CEA) mortars achieve insufficient bond strength with substrate cement concrete slab. To ameliorate problems emerging from this, the emulsified asphalt (EA) in CEA mortars was partly replaced by epoxy emulsion (EE) at contents of 0%, 10%, 20%, and 30%, yielding CEA mortars with enhanced properties. The bond strength, mechanical strength, toughness, and durability (including drying shrinkage and erosion resistance) of modified CEA mortars were assessed. The results showed that partial replacement of EA with EE improved the bond strength, mechanical strength, drying shrinkage, and erosion resistance of CEA mortars. A good correlation was found between the proportions of the EE replacement and the bond strength of CEA mortars. Partial replacement of EA with a small amount of EE exerted no significant effect on the toughness of CEA mortar. The stronger network structure of CEA mortars containing EE improved the compactness, thus improving the performance of CEA mortars. Based on these findings, EE is suggested as partial replacement of EA for enhancing the properties of CEA mortars.

Download Full-text

The use of aluminum slag waste in the preparation of roof tiles

Materials Research Express ◽

10.1088/2053-1591/ac3bf7 ◽

2021 ◽

Author(s):

Marwa Ahmed ◽

M. F. Abadir ◽

Ayman Yousef ◽

K. A. M. El-Naggar

Keyword(s):

Mechanical Strength ◽

Water Absorption ◽

Cold Water ◽

Breaking Strength ◽

Drying Shrinkage ◽

Smelting Process ◽

Minimum Requirement ◽

Roof Tile ◽

Slag Waste ◽

Clay Type

Abstract Aluminum slag waste generated from the smelting process of bauxite was used to prepare roof tiles samples. Clay was substituted by slag waste in percentages reaching 40% in the basic mix and the plasticity of the obtained mud was determined. This was followed by pressing the mud in steel molds and drying. The effect of waste addition on drying shrinkage was subsequently assessed. Firing of the green bodies was carried out at three temperatures (900, 1000 and 1100oC) and hour soaking at each temperature. Fired roof tile properties improved on increasing the percentage of alumina sludge and firing temperature possibly because of the presence of high amounts of fluxing oxides in aluminum slag. This caused a drop in porosity that increased the mechanical strength of tiles. The results showed that the substitution of clay by 40% waste and firing at 1100oC resulted in products conforming to ASTM C-1167 for clay type roof tiles. Cold water absorption dropped to 12%, below the maximum permissible limit of 15%, the value of Saturation Coefficient was 0.83, below the 0.86 limit and the obtained breaking strength of 3370N significantly exceeded the minimum requirement of 890N.

Download Full-text

Effect of limestone powder on self-compacting concrete

FES Journal of Engineering Sciences ◽

10.52981/fjes.v9i2.680 ◽

2021 ◽

Vol 9 (2) ◽

pp. 71-78

Author(s):

O. M. A. Daoud ◽

O. S. Mahgoub

Keyword(s):

Construction Material ◽

Control Sample ◽

Drying Shrinkage ◽

Heat Of Hydration ◽

Limestone Powder ◽

Partial Replacement ◽

Self Compacting Concrete ◽

Technical Problems ◽

Cement Replacement ◽

Partial Cement Replacement

Self-compacting concrete (SCC) is an innovative construction material in the construction industry. It is a highly fluid and stable concrete that flows under its own weight and fills completely the formwork. The SCC requires high powder content (mainly of cement) up to 600kg/ to achieve its properties. This will be problematic because increasing the cement content is not feasible, and may cause high cost and some other technical problems such as higher heat of hydration and higher drying shrinkage. This paper investigates the effect of limestone powder (LSP) on fresh and hardened properties of SCC due to the use of LSP as a partial cement replacement. For comparison, a control sample of concrete was prepared without LSP to compare it with the various samples containing different percentages of LSP as a partial replacement of cement. Four mixes with a constant amount of (superplasticizer, sand, coarse aggregate, and water) at various replacement levels of 0%, 10%, 20% and 30% from the cement weight were prepared. The experimental results show that the LSP can be effectively used as a partial cement replacement on SCC to reduced cost and enhanced the performance of SCC in fresh and hardened stages.

Download Full-text

Influence Of Volcanic Scoria On Mechanical Strength, Chemical Resistance And Drying Shrinkage Of Mortars

Building Research Journal ◽

10.2478/brj-2014-0011 ◽

2014 ◽

Vol 61 (3) ◽

pp. 143-150 ◽

Cited By ~ 1

Author(s):

A. Al-Swaidani ◽

S. Aliyan ◽

N. Adarnaly ◽

B. Hanna ◽

E. Dyab

Keyword(s):

Mechanical Strength ◽

Sulphuric Acid ◽

Chemical Resistance ◽

Control Sample ◽

Acid Resistance ◽

Drying Shrinkage ◽

Strength Development ◽

Acid Solutions ◽

Test Results ◽

Blended Cements

Abstract In the study, three types of cement have been prepared; one CEM I type (the control sample) and two blended cements: CEM II/A-P and CEM II/B-P (EN 197-1), each of them with three replacement levels of volcanic scoria: (10 %, 15 %, 20 % wt.) and (25 %, 30 %, 35 % wt.), respectively. Strength development of mortars has been investigated at 2, 7, 28 and 90 days curing. Evaluation of chemical resistance of mortars containing scoria-based cements has been investigated through exposure to 5 % sulphate and 5 % sulphuric acid solutions in accordance with ASTM C1012 & ASTM 267, respectively. Drying shrinkage has been evaluated in accordance with ASTM C596. Test results showed that at early ages, the mortars containing CEM II/B-P binders had strengths much lower than that of the control mortar. However, at 90 days curing, the strengths were comparable to the control mortar. In addition, the increase of scoria significantly improved the sulphate resistance of mortars. Further, an increase in scoria addition improved the sulphuric acid resistance of mortar, especially at the early days of exposure. The results of drying shrinkage revealed that the CEM II/B-P mortar bars exhibited a greater contraction when compared to the control mortar, especially at early ages. However, drying shrinkage of mortars was not influenced much at longer times.

Download Full-text

Mechanical and Durability Properties of Cement-Stabilized Recycled Concrete Aggregate

Sustainability ◽

10.3390/su12187380 ◽

2020 ◽

Vol 12 (18) ◽

pp. 7380

Author(s):

Qingfu Li ◽

Jing Hu

Keyword(s):

Cement Content ◽

Drying Shrinkage ◽

Recycled Concrete ◽

Partial Replacement ◽

Concrete Aggregate ◽

Curing Time ◽

Recycled Concrete Aggregate ◽

Replacement Ratio ◽

Obvious Effect ◽

Study Test

This research investigates the effect of using recycled concrete aggregate (RCA) as a partial replacement of natural aggregate (NA) on the mechanical and durability-related properties of a cement-stabilized recycled concrete aggregate (CSR) mixture. In this case, mixtures were prepared with 0%, 40%, 70%, and 100% (by weight) RCA to replace NA, and cement contents of 4%, 5%, and 6% were used in this study. Test parameters included the replacement ratio, cement content, and curing time. Tests were carried out to establish the unconfined compressive strength (UCS), indirect tensile strength (ITS), drying shrinkage, and water loss ratio of each mix proportion. The preliminary results of UCS and ITS tests indicated that the incorporation of RCA resulted in a decrease of strength compared with a cement-stabilized macadam (CSM) mixture, but the seven-day strength of the CSR mixture met the related requirements of road bases. The increase in cement content and curing time had an obvious effect on strength improvement. The drying shrinkage test showed that the drying shrinkage properties of the CSR mixture were obviously reduced with a high replacement ratio. It is evident that the CSM mixture presented a better drying shrinkage performance than that of the CSR mixture.

Download Full-text

Experimental Examination on Mechanical Properties of Polypropylene Fiber Blended Concrete as Partial Replacement of Sand as Stone Quarry Dust

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.g5489.059720 ◽

2020 ◽

Vol 9 (7) ◽

pp. 623-627

Keyword(s):

Mechanical Properties ◽

Polypropylene Fiber ◽

Construction Materials ◽

Drying Shrinkage ◽

Partial Replacement ◽

Normal Stresses ◽

Experimental Examination ◽

Concrete Members ◽

Maximum Value ◽

Quarry Dust

Concrete is recognized as a quite breakable material when exposed to impact loading and normal stresses. Concrete tensile strength is nearly one-tenth of its compressive strength. As a result of which concrete members are not able to support such stresses and loads which mainly occurs in most concrete structures. So, we mainly reinforce it with such materials which help it to increase its tensile and flexural strength. Fibers are the material which helps to increase the toughness and durability of concrete and reduce plastic and drying shrinkage. As we know cement, sand and aggregate are three basic construction materials. Due to the huge demand for these materials, their deposits are scarce. So, we need to find the material which can replace them partially and fully. Stone quarry dust is material that may be used to replace sand partially and fully. In this study, the casting of moulds for various percentage of stone quarry dust (5%, 10%, 20%, 30%, 40%, and 50%) is carried and maximum value for stone quarry dust is obtained. After obtaining the max value of stone quarry dust at 10% it is replaced with various percentages of polypropylene fiber (0%, 0.1%, 0.2% and 0.3%). This study aims to investigate the limit up to which stone quarry can be replaced with sand for M35 grade of concrete and to investigate the combined effect of stone quarry dust (10%) and polypropylene fiber with varying percentage (0%, 0.1%, 0.2%, and 0.3%).

Download Full-text

Properties of concrete containing recycled concrete aggregate of preserved quality

10.32920/ryerson.14664390 ◽

2021 ◽

Author(s):

Jonathan Andal

Keyword(s):

Coarse Aggregate ◽

Drying Shrinkage ◽

Recycled Concrete ◽

Partial Replacement ◽

Concrete Aggregate ◽

Recycled Concrete Aggregate ◽

Salt Scaling ◽

Concrete Properties ◽

Comparable Quality ◽

Scaling Resistance

Today, there is a growing need for the implementation of sustainability in construction. Continuous construction and rehabilitation projects have begun to deplete virgin aggregate sources. The use of recycled concrete aggregate (RCA) in concrete has been regarded as a sustainable and environmentally friendly alternative aggregate source. This thesis focuses on producing RCA of preserved quality through the use of a new protocol aimed at maintaining the original properties of returned-to-plant concrete. The performance of RCA with preserved quality and commercially available RCA when used in concrete was compared. Different concrete properties were evaluated including the fresh, hardened and durability characteristics. Results showed that the RCA with preserved quality performed better in many categories, including strength, drying shrinkage and salt scaling resistance compared to the commercial RCA. The use of 30% preserved-quality RCA as partial replacement of coarse aggregate produced concrete of comparable quality to that produced with virgin aggregate.

Download Full-text

Effects of a Natural Mordenite as Pozzolan Material in the Evolution of Mortar Settings

Materials ◽

10.3390/ma14185343 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5343

Author(s):

Jorge L. Costafreda ◽

Domingo A. Martín ◽

Leticia Presa ◽

José Luis Parra

Keyword(s):

Compressive Strength ◽

Portland Cement ◽

Mechanical Strength ◽

Setting Time ◽

Volcanic Glass ◽

Positive Influence ◽

Partial Replacement ◽

X Ray ◽

Initial Setting Time ◽

Pozzolanic Cement

This paper shows the results of a study focused on the evolution and properties of mortars made with a mixture of portland cement (PC) and natural mordenite (Mor). To begin, samples of mordenite, cement and sand were studied with X-ray diffraction (XRD), X-ray fluorescence (XRF) and granulometric analysis (GA). Next, mortars with a ratio of 75% PC and 25% mordenite were prepared to determine their initial and final setting times, consistency and density. Continuing, the density, weight and compressive strength of the specimens were determined at 2, 7, 28, 90 and 365 days. Finally, the specimens were studied using SEM, XRD and XRF. The results of the study of the mordenite sample showed a complex constitution where the major mineral component is mordenite, and to a lesser degree smectite (montmorillonite), halloysite, illite, mica, quartz, plagioclase and feldspar, in addition to altered volcanic glass. Tests with fresh cement/mordenite mortar (CMM) showed an initial setting time of 320 min and a final setting time of 420 min, much longer than the 212–310 min of portland cement mortar (PCM). It was established that the consistency of the cement/mordenite mortar (CMM) was greater than that of the PCM. The results of the density study showed that the CMM has a lower density than the PCM. On the other hand, the density of cement/mordenite specimens (CMS) was lower than that of portland cement specimens (PCS). The CMS compressive strength studies showed a significant increase from 18.2 MPa, at 2 days, to 72 MPa, at 365 days, with better strength than PCS at 28 and 365 days, respectively. XRD, XRF and SEM studies conducted on CMS showed a good development of primary and secondary tobermorite, the latter formed at the expense of portlandite; also, ettringite developed normally. This work proves that the partial replacement of PC by mordenite does not have a negative effect on the increase in the mechanical strength of CMS. It indicates that the presence of mordenite inhibits the spontaneous hydration of C3A and controls the anomalous formation of ettringite (Ett). All this, together with the mechanical strength reported, indicates that mordenite has a deep and positive influence on the evolution of the mortar setting and is an efficient pozzolan, meaning it can be used in the manufacture of mortars and highly resistant pozzolanic cement, with low hydration heat, low density, stability in extremely aggressive places and a low impact on the environment.

Download Full-text

Drying Shrinkage of Fly Ash Mortar Mixed with Seawater

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.802.118 ◽

2015 ◽

Vol 802 ◽

pp. 118-123 ◽

Cited By ~ 1

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.

Download Full-text

Long-Term Behavior of Low-Heat Cement Concrete under Different Curing Temperatures

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.723.819 ◽

2016 ◽

Vol 723 ◽

pp. 819-823 ◽

Cited By ~ 1

Author(s):

Jae Sung Mun ◽

Keun Hyeok Yang ◽

Si Jun Kim

Keyword(s):

Drying Shrinkage ◽

Curing Temperature ◽

Limestone Powder ◽

Partial Replacement ◽

Mass Concrete ◽

Test Results ◽

Long Term Behavior ◽

Ambient Curing ◽

Ternary Blended Concrete

The present study is to estimate long-term characteristics of low-heat cement-based ternary blended concrete prepared for reducing hydration heat in mass concrete. 15% modified fly ash and 5% limestone powder were added for partial replacement of the low-heat cement. To achieve the designed compressive strength of 42 MPa, water-to-binder ratios were determined to be 27.5, 30 and 32.5% for ambient curing temperatures of 5, 20 and 40°C, respectively. Test results showed that, with the decrease in curing temperature, the drying shrinkage strains tended to decrease, whereas creep strain increased.

Download Full-text