Effects Of Temperature Curing Research Articles

Effect of Ground Granulated Blast Slag and Temperature Curing on the Strength of Fly Ash-based Geopolymer Concrete

Concrete is used most extensively after water to meet construction requirements. Since the population is increasing day by day, the demand for concrete will always increase, hence, the demand for cement will also increase. The production of cement requires a lot of energy and emits greenhouse gases into the environment. Therefore, an alternative material for cement concrete is required. Geopolymer concrete (GPC) is an alternative to cement made of aluminosilicate materials such as fly ash, Ground Granulated Blast Slag (GGBS), silica fume, metakaolin, etc. If these materials are activated with an alkaline activator, then a bond that is responsible for the strength develops. GPC made with fly ash needs temperature curing to develop its strength, which limits its use on a large scale. In this study, a mix ratio of GPC equivalent to conventional M20 concrete was obtained at ambient curing conditions. The effect of temperature curing was also studied. GPC was prepared in three different mixes. In each mix, the binder content was changed by varying the fly ash and GGBS content. Two sets of cube, beam, and cylindrical samples were prepared from each mixture. One set was cured at ambient temperatures and the other at increased temperatures. The temperature-cured specimens provided higher strength than the ambient-cured. If a strength equivalent to conventional M20 concrete is required for ambient curing, then the mix should be 70% fly ash and 30% GGBS, and the ratio of binder, fine aggregate, and coarse aggregate should be 1:1.5:3.

The effect of temperature curing on total petroleum hydrocarbon (TPH) values of slag-based polluted sample leachate

Alkaline activation is noteworthy in manufacturing due to its environmental implications since it enables the use of waste materials containing amorphous SiO2 and Al2O3 as initial components. Herein, stabilization/solidification (S/S) using the alkaline activation of granulated blast furnace slag (GBFS) was used to reduce the total petroleum hydrocarbon (TPH) of the crude oil-polluted sample leachate. By producing cementitious products and reducing the pore spaces of the oil-contaminated soil, the alkaline activation of slag created a dense structure and significantly lowered TPH. By raising the curing temperature, the TPH reduction intensity increased and reached > 60 %. Besides helping the circular economy by extracting high-quality resources from waste, this method controls oil pollution spread and decreases environmental pollution as it replaces cement and lime.

Effect of temperature curing on properties and hydration of wollastonite blended magnesium potassium phosphate cements

K-struvite, the main hydrate of magnesium potassium phosphate (MKP) cements, dehydrates at ~50 °C, thus elevated temperatures at service conditions could affect cement properties and durability. In this study, properties and hydration of MKP cement without and with wollastonite were investigated at 20 and 50 °C. In hydrated pure MKP cement K-struvite decomposes progressively over time to MgKPO4·H2O at 50 °C, which leads to a strong reduction of solid volume and severe strength loss. The presence of wollastonite significantly slows down the decomposition rate of K-struvite, which is still observed after 393 days at 50 °C. K-struvite together with amorphous hydroxyapatite, M-(C)-S-H and CaK3H(PO4)2 from the wollastonite reaction result in a cement with good short and long-term strength at both 20 and 50 °C.

The Effects of Temperature Curing on the Strength Development, Transport Properties, and Freeze-Thaw Resistance of Blast Furnace Slag Cement Mortars Modified with Nanosilica.

This investigation studies the effects of hot water and hot air curing on the strength development, transport properties, and freeze-thaw resistance of mortars incorporating low-heat blast furnace slag cement and nanosilica (NS). Mortar samples were prepared and stored in ambient conditions for 24 h. After demolding, mortar samples were subjected to two different hot curing methods: Hot water and hot air curing (40 °C and 60 °C) for 24 h. For comparison purposes, mortar reference mixes were prepared and cured in water and air at ambient conditions. Strength development (from 1 to 180 days), capillary water porosity, water sorptivity, and freeze-thaw resistance were tested after 180 days of curing. The experimental results showed that both curing regimes accelerate the strength development of mortars, especially in the first seven days of hydration. The highest early strengths were reported for mortars subjected to a temperature of 60 °C, followed by those cured at 40 °C. The hot water curing regime was found to be more suitable, as a result of more stable strength development. Similar findings were observed in regard to durability-related properties. It is worth noting that thermal curing can more efficiently increase strength in the presence of nanosilica, suggesting that NS is more effective in enhancing strength under thermal curing.

Effect of temperature curing on lightweight expanded clay aggregate concrete

Lightweight Aggregate Concrete is usually a mix of Lightweight Aggregates and admixtures. This paper is focused on use of Lightweight Expanded Clay Aggregate (LECA) for the development of structural Lightweight Concrete. The present investigation was carried out by replacing LECA with 30% of Normal Weight Aggregate (NWA) with different water to binder (w/b) ratios to produce an M 30 grade Lightweight Expanded Clay Aggregate Concrete i.e. LECAC30 (30% LECA + 70% NWA). LECAC30 was cured with potable water at boiling temperature for different durations like 3hrs, 6hrs and 9hrs and the effect of temperature curing on early development of compressive strength of Lightweight Expanded Clay Aggregate Concrete was studied. The study also includes the improvement of compressive strength of LECAC30 under temperature curing with 10% addition of mineral admixture. The results obtained in this research conclude that, optimum duration for temperature curing at 100°c was obtained as 6 hrs, the addition of mineral admixture to LECAC30 resulted in an improvement of compressive strength and addition of mineral admixture had no significance in early development of compressive strength under temperature curing.

Effect of lime stabilization on the mechanical and micro-scale properties of recycled demolition materials

Sustainable reuse options for Construction and Demolition (C&D) materials in civil engineering applications have been an emerging topic in recent years. Crushed Brick (CB), Recycled Crushed Concrete (RCA) and Reclaimed Asphalt Pavement (RAP) comprise a major fraction of the wastes going to landfills. This research investigates the performance of lime stabilized C&D materials as road materials. Tests were undertaken on unbound and lime stabilized C&D materials with 1% to 5% hydrated lime. The laboratory investigation included particle size distribution, California Bearing Ratio, modified Proctor compaction, Repeated Load Triaxial (RLT) test and Unconfined Compressive Strength (UCS) tests. The effect of temperature curing, up to 40°C was investigated and compared to ambient temperature. The resilient modulus results indicated that the lime stabilized RCA and CB were viable options for construction of subbase layers of pavement while RAP did not meet the requirements of a road construction material. UCS values of RCA and CB met the minimum requirement for cementitious materials after 7days of curing. In addition to evaluating the mechanical properties, micro-scale analyses were also conducted using Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) to understand the behavior of the lime stabilization of C&D materials.

The Effect of Temperature Curing on Geopolymer Concrete

This study presents curing temperature influences to behaviors of geopolymer concrete. The concrete was fly ash based, with the ratio of fly ash to alkaline activator was 65%:35%. Ratio coarse aggregate to fine aggregate was 60%:40%, ratios Na 2 SiO 3 /NaOH were 1.5:2 and 2.5. A polycarboxilate superplasticizer with ratio was 2% to fly ash weight. Form of the test specimens were cylinder with diameter of 10 cm and 20 cm high. Steam curing conducted were at 40°C, 60°C and 80°C for 24 hours. The control specimens were treated at normal moist curing. Tests conducted were compressive strength, tensile strength, porosity and elasticity modulus. The results indicated that at the elevated temperature the compressive strength increases as well as tensile strength but decreases the closed porosity of specimens. The elasticity modulus had a similar tendency.

THE EFFECT OF CURING CONDITION ON COMPRESSIVE STRENGTH IN HIGH STRENGTH CONCRETE

The paper shows the effect of curing condition on compressive strength in high strength concrete in three cases (Group A(moist curing in water for 7 days followed by air curing ) ,Group B(curing until the age test in water) and Group C(curing at high temperature 60ºC±2ºC for six days ) and two types of specimen of cubes (150 x150 and 100 x 100) used in the test age (7,28and 90 day) respectively in four mix proportion (Mix No.1(40 Mpa ,Mix No. 2(fcu 60 Mpa) ,Mix No. 3 (fcu 70 Mpa) and Mix No. 4 (fcu 80 Mpa) ). Results demonstrate that, in general, concrete specimens moist cured until testing ages (Group B) give compressive strength greater than specimens moist cured for 7 days in water then followed by air – drying (Group A). The percentage of increase in strength is (5 and12%) for mix No.3 and 6% for mix No.4, as compared with 3% for mix No.1 and (2 and4%) for mix No.2. When the curing temperature (group C ) increases, the compressive strength increases at different ratios ,the percentage of increase in compressive strength at 7,28 and 90 days for mix No.1 , mixes No.2 and 3 are (20,15 and 14% ), ( 7,11 and 5% ) and (13,12 and 5% ) respectively, while mix No4. shows an increase of 4 and 10% in compressive strength at 7 and 28 days where there is a reduction in the strength at 90 days by about 2%. Generally, as the size of specimen decreases, the effect of temperature curing (group C)on the compressive strength increases.