scholarly journals Pengaruh Air Laut sebagai Air Pencampur dan Air Perawatan pada Karakteristik Pasta Semen dan Mortar

2018 ◽  
Vol 5 (1) ◽  
pp. 28
Author(s):  
Adiwijaya Ali ◽  
Irka Tangke Datu

The goal of this research is to investigate the influence of seawater as mixing water and curing water on characteristics of cement paste and mortar. Research was conducted with making mixtures of cement paste and mortar using two kind of cement, Portland Composite Cement (PCC) and Pozzolana Portland Cement (PPC) with seawater as mixing water. Characteristics of fine aggregate and characteristics of cement paste with seawater mixing were investigated. Furthermore, 144 cube mortar specimens in size of 5 cm x 5 cm x 5 cm in four series mortar mixtures were casted according with SNI 03-6825-2002. At 24 hours after specimens were casted, cube mortar specimens were cured in tap water curing (TC), seawater curing (SC) and air curing (AC). After achievement at certain curing day of 3, 7, 14 and 28 days, cube mortar samples were tested in compressive strength. Results concluded that seawater mixing improves compressive strength of mortar up to 28 days in all curing conditions, TC, SC and AC. Moreover, strength of mortar is not affected by type of curing water, tap water or seawater.

2021 ◽  
Vol 7 (2) ◽  
pp. 160
Author(s):  
Irka Tangke Datu ◽  
Adiwijaya Ali ◽  
Nur Aisyah Jalali ◽  
Khairil Khairil

This present paper aims to investigate strength characteristics of cement mortar using natural sea sand as fine aggregate in different curing conditions. Research was carried out with making mortar mixtures by two types of cement, Portland Composite Cement (PCC) and Pozzolana Portland Cement (PPC) with tap water as mixing water. Characteristics of fine aggregate and strength of cement mortar use river sand (RS), sea sand (SS), and washed sea sand (WS) were observed. Further, specimens of cube mortar in size of 50 mm x 50 mm x 50 mm of six mortar mixture series were casted according to Indonesian Standard. At 24 hours after cube specimens were casted, cube mortar specimens were cured in three curing conditions such as tap water curing (TC), seawater curing (SC) and air curing (AC). After curing at certain period (3-day, 7-day, 14-day, and 28-day), cube mortar samples were tested in compressive strength. Results concluded that sea sand aggregate improve characteristic of mortar in compressive strength up to 28 days in all curing conditions, and there was no significant effect of type of curing water (TC and SC) on 28-day strength performance of mortar was obtained. In addition, sea sand could potentially be utilized as an aggregate in production of mortar and/or concrete.


2010 ◽  
Vol 1 (2) ◽  
pp. 1-6 ◽  
Author(s):  
Aminur M.R ◽  
Harunur M.R ◽  
Teo D.C.L ◽  
Abu Zakir M.M

The present research describes the effect of aggregate and curing condition on the compressive strength of concrete with age. Ordinary Portland cement, coarse sand and brick chips/pebble gravels were used as binder, fine aggregate and coarse aggregate respectively. The ratio of cement, sand and coarse aggregate was 1:2:4 by weight. Five different curing conditions namely, water curing (WC), self curing (SC), air dry curing (ADC), one-day delay curing (1-DC) and three-days delay curing (3-DC) were employed. Two types of concrete namely; concrete C1 (brick chips as coarse aggregate) and C2 (pebbles gravel as coarse aggregate) were prepared in this study. The physical and mechanical properties of aggregates and concrete were determined respectively. The results show that, the compressive strength of concrete is affected by the properties of the aggregate and also curing condition employed. It was found that, the concrete C1 and the normal water curing appeared to be better than concrete C2 and other types of curing condition.


Author(s):  
Miguel Picornell ◽  
Sameer Hamoush ◽  
Taher Abu-Lebdeh

This research study investigates the effect of fly ash and silica fume on the cement paste hydration. A total of 350 samples of different percentages of each additive were tested and compared with the controlled cement paste without additives. Testing method includes water curing and vacuum curing conditions and involves the use of Forney Universal Testing Machine and MTS Landmark Servohydraulic Testing System (MTS) for compressive strength; Fourier Transfer Infrared Spectroscopy (FTIR) monitored the hydration with spectra; and Scanning Electron Microscope (SEM) generated images for regional analysis. Compressive strength testing demonstrated that silica fume replacement had the highest overall strength under water curing. Replacement of fly ash exhibited the highest overall strength under vacuum curing. The hydration process was monitored with the use of FTIR and SEM. Signatures of CSH which produce most of the concretes’ strength, has been determined and examined from 3 to 56 days. FTIR and SEM testing showed an increase in the change of CSH area with age. SEM testing revealed the formation of pores, CSH, and CH in images at all ages. The area of CSH grows most in early ages and diminishes over time. It is clear that the method of curing makes a difference in hydration. Results indicated that the area at which the possible formation of CSH was determined from each sample, has increased with respect to time; signifying the increase in strength over the course of testing days.


2019 ◽  
Vol 2 (2) ◽  
pp. 65
Author(s):  
Purwanto P. ◽  
Himawan Indarto

Portland cement production process which is the conventional concrete constituent materials always has an impact on producing carbon dioxide (CO2) which will damage the environment. To maintain the continuity of development, while maintaining the environment, Portland cement substitution can be made with more environmentally friendly materials, namely fly ash. The substitution of fly ash material in concrete is known as geopolymer concrete. Fly ash is one of the industrial waste materials that can be used as geopolymer material. Fly ash is mineral residue in fine grains produced from coal combustion which is mashed at power plant power plant [15]. Many cement factories have used fly ash as mixture in cement, namely Portland Pozzolan Cement. Because fly ash contains SiO2, Al2O3, P2O3, and Fe2O3 which are quite high, so fly ash is considered capable of replacing cement completely.This study aims to obtain geopolymer concrete which has the best workability so that it is easy to work on (Workable Geopolymer Concrete / Self Compacting Geopolymer Concrete) and obtain the basic characteristics of geopolymer concrete material in the form of good workability and compressive strength. In this study, geopolymer concrete is composed of coarse aggregate, fine aggregate, fly ash type F, and activators in the form of NaOH and Na2SiO3 Be52. In making geopolymer concrete, additional ingredients such as superplastizer are added to increase the workability of geopolymer concrete. From this research, the results of concrete compressive strength above fc' 25 MPa and horizontal slump values reached 60 to 80 centimeters.


2021 ◽  
Vol 4 (2) ◽  
pp. 12-18
Author(s):  
D.A. Tolypin ◽  
N. Tolypina

the article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a crite-rion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the con-crete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on tra-ditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap al-lows obtaining building composites based on it with the complete exclusion of natural raw materials


Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Gökhan Kaplan ◽  
Hasbi Yaprak ◽  
Selçuk Memiş ◽  
Abdoslam Alnkaa

The use of mineral admixtures and industrial waste as a replacement for Portland cement is recognized widely for its energy efficiency along with reduced CO2 emissions. The use of materials such as fly ash, blast-furnace slag or limestone powder in concrete production makes this process a sustainable one. This study explored a number of hardened concrete properties, such as compressive strength, ultrasonic pulse velocity, dynamic elasticity modulus, water absorption and depth of penetration under varying curing conditions having produced concrete samples using Portland cement (PC), slag cement (SC) and limestone cement (LC). The samples were produced at 0.63 and 0.70 w/c (water/cement) ratios. Hardened concrete samples were then cured under three conditions, namely standard (W), open air (A) and sealed plastic bag (B). Although it was found that the early-age strength of slag cement was lower, it was improved significantly on 90th day. In terms of the effect of curing conditions on compressive strength, cure W offered the highest compressive strength, as expected, while cure A offered slightly lower compressive strength levels. An increase in the w/c ratio was found to have a negative impact on pozzolanic reactions, which resulted in poor hardened concrete properties. Furthermore, carbonation effect was found to have positive effects on some of the concrete properties, and it was observed to have improved the depth of water penetration. Moreover, it was possible to estimate the compressive strength with high precision using artificial neural networks (ANN). The values of the slopes of the regression lines for training, validating and testing datasets were 0.9881, 0.9885 and 0.9776, respectively. This indicates the high accuracy of the developed model as well as a good correlation between the predicted compressive strength values and the experimental (measured) ones.


Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 133 ◽  
Author(s):  
Esteban Estévez ◽  
Domingo Alfonso Martín ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán

The purpose of this paper is to establish some correlations between the main technical parameter with regard to the cement-based materials technology, the 28-day compressive strength, and ultrasonic pulse velocity of standard mortar samples cured at three different conditions—(i) under water at 22 °C; (ii) climatic chamber at 95% RH and 22 °C; (iii) lab ambient, 50% RH, and 22 °C—and after five curing periods of 1, 2, 7, 14, and 28 days. Good correlations for each curing conditions were obtained. All the positive linear relationships showed better R2 than exponential ones. These findings may promote the use of ultrasonic pulse velocity for the estimation of the 28-day compressive strength of standard Portland cement samples within the factory internal quality control.


2019 ◽  
Vol 262 ◽  
pp. 06002 ◽  
Author(s):  
Magdalena Dobiszewska ◽  
Waldemar Pichór ◽  
Paulina Szołdra

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.


2011 ◽  
Vol 147 ◽  
pp. 3-8
Author(s):  
Haleem K. Hussain ◽  
Liu Gui Wei ◽  
Hameed A. Hamdi ◽  
Dawood S. Abed

This study reported the results of adding furfural on mechanical properties of Ordinary Iraqi cement. Furfural was used at four different ratios (1%, 2%, 3%, and 5 %) by weight to the mix of Iraqi Portland cement (Um- Quasar factory cement). The effect on the plasticizing and fluidity by table flow test for cement paste and slump test of fresh concrete were studied. The obtained results showed that added furfural is acting as super plasticizer. Effective relation was found between fluidity and ratio of added through effecting time of flow where the most effect additive ratio was found to be 3% .The radius of cement paste circle is linearly dependence which is a indicate of high workability. Obtained results explained in term of electrical charges on cement particles. Also found that adding furfural increasing the dispersion work between cement paste particles and preventing coarse agglomerated. The using of furfural with concrete indicates two kinds of concrete behavior. These behaviors were strongly dependence on furfural ratio .The critical value of added furfural was 1% and after which a plasticizing effect obtained. Splitting and flexural tensile test were conducted. Three types of curing methods include dry, moisture and water curing. The obtained results showed that the moisture curing was better than other curing methods due to good results obtained with splitting tensile (6.18 N/mm2) for 5% ratio and water curing is preferred for flexural tensile (7.05 N/mm2 at 2% wt% of furfural ). Finally, we compared our results with AL-Abraaj Kuwait cement and we found that the Iraqi cement (Um Quasar factory cement) was better.


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