Ggbs concrete by ecocem ggbs improves longterm strength, protects concrete from aggressive chemical attack, reduces heat of hydration, and makes concrete more workable. The durability of ground granulated blast furnace slag ggbs concretes and the corrosion behavior of reinforced concrete beams under various loading ratios were investigated. The autogenous healing mechanism of concrete cracks is roughly divided into. Yes ggbs is a good partial replacement for cement in concrete mix.
Under water concrete with ground granulated blast furnace. Is ggbs a good partial replacement for cement in concrete. Example blending it with 70% of ggbs psc will have 70% ggbs and opc 30% total will some to 100%. Using ggbs as an additive in concrete mixes can reduce embodied carbon and. Groundgranulated blastfurnace slag ggbs or ggbfs is obtained by quenching molten iron slag a byproduct of iron and steelmaking from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder.
Ground granulated blastfurnace slag ggbs is a green construction material used to produce durable concrete. Ggbs, which is a byproduct of the manufacturing of iron in the blast furnace, can partially replace cement in concrete. Water distribution and transport, whether in gaseous or. During this process, the slag gets fragmented and transformed into amorphous granules glass, meeting the requirement of is 12089. Pdf strength and durability studies on ggbs concrete. The aspect that most concerns people is the lower early age strength. Repairing the gypcrete involves sweeping away any dust caused by the crumbling material. Blastfurnaces are fed with controlled mixture of ironore, coke and. To evaluate the mechanical characteristics of concrete such as compressive strength, split tensile test, flexural strength. With the addition of 40% of ggbs as a replacement of cement for an m25 grade of concrete, there is an increase in the strength compared to the normal concrete. The reaction of the ggbs particles is also slower which makes it suitable for mass pours as the risk of thermal cracking is reduced. Water table for this site is 6m below natural ground level.
Study on strength properties of concrete using ggbs and steel fiber as partial replacement of cement dhanya r 1, arasan g. More than 5,000,000 tonnes of ggbs produced in germany 2006. Groundgranulated blastfurnace slag ggbfs is a byproduct of iron and steelmaking obtained by quenching molten iron slag from a blast furnace in water or steam. Ggbs concrete the cementitious slag makers association. Another major hurdle of extensive use of ggbs concrete lies in the little source of supply of ggbs. Strength and corrosion resistance properties of ggbs. Results and discussion concrete with process fly ash, when the percentage of ggbs replaced to cement with varying percentage from 25% to 40% the following results were drawn. This is due to the evaporation of excess mixing water.
This shrinkage causes forces in the concrete which literally pull the slab. In the ggbs specimens there was no visible cracking after exposure to the higher temperatures. Concrete repair and repair products the concrete network. Very occasionally, it can be found up to a ratio of 90% ggbs and 10% pc. Used at the appropriate replacement rate there are little or no disadvantages. Portland cement substitution with fly ash, or the concrete with 50%. Hydraulic potential of ggbs discovered in germany early 1900s portland blast furnace cements had an established place in the concrete market 2004. Which of the following cement replacement material is. Partial replacement of cement with ggbs in concrete. Th r esults of c ompressive t est at 28 day specimen 2 compressive strength nmm control concrete 32. The main variables were the replacement of cement by ggbfs 1550% and.
Blast furnace slag cement for durable marine structures. Durability properties and microstructure of ground. High strength concrete incorporating ground granulated. Partial replacement of cement with ggbs in self compacting. Ggbs is replaced for cement in the level of 10%, 20%, 30%, 40%, 50% and 60%. As hong kong is not a major producer of steel, ggbs as a byproduct of steel has to be imported overseas and this introduces higher material cost due to transportation and the supply of. The use of ggbs in concrete has proved to improve certain properties, when compared to portland cement concretes.
This material is obtained by the heating of iron ore, limestone and coke at a temperature about 1500 degree celsius. The main reason for incorporating fibers into a cement matrix is to increase the tensile strength, the energy absorption capacity, toughness, flexural strength of concrete and also it improves the cracking deformation characteristics of the concrete composite. Ggbs reduces the risk of sulfate attack on the concrete. Durability of ggbs concrete 0% ggbs 30% ggbs 50% ggbs 40. Benefits of using ggbs cement in large concrete pours. Ggbs expands concrete lifespan and durability lkab minerals. Heat of hydration and early age thermal cracking hardened concrete the rate of hydration reaction of ggbs concrete is temperature dependent. However, some concerns regarding its performance in freezing environments have been raised. It is suggested that ggbs is generally beneficial in extending the life of concrete, and that this effect is especially important where the attack is the result of the movement of aggressive ions.
This usage of ggbs serves as replacement to already depleting conventional building materials and the recent years and also as. Ground granulated blast furnace slag ggbs1 is a by product from the blast furnaces used to make iron. The benefits of ggbs cement in concrete 2011 engineers. Introduction to ground granulated blastfurnace slag. Once you have a clean surface, apply the floorleveling product or mortar to the damaged areas. The enhanced control of thermal movement also contributes to better and longterm performance of concrete. Ground granulated blast furnace slag ggbs jsw cement. After grinding it is stored in silo and then sent for delivery through bag packs or in bulker as loose cement. The secondary pozzolanic reactions can result in reduced pore connectivity. Anecdotal evidence suggests cracking of concrete structures and components appears to be on the rise, often resulting in conflict between involved parties.
The rate of chloride transport by diffusion in concrete containing ground granulated blastfurnace slag ggbs was mathematically estimated to predict the corrosionfree service life of concrete structures exposed to seawater environment. Control of cracking in concrete transportation research board. Used to increase the strength of concrete and used to improve workability of fresh concrete and reduce water demand, shrinkage and permeability of the finished product. I had practically used ppc cement in almost all projects. Concrete members will expand and contract when exposed to hot and cold.
Heat of hydration ggbs lowers peak and overall heat reduces thermal stressing reduces microcracking particularly useful in water retaining structures, basements, podium slab, bridges, stadiums, secant pile walls etc etc. Estimation of corrosionfree life for concrete containing. Blast furnace slag cement concrete is a versatile material of low environmental. These operate at a temperature of about 1500 degrees centigrade and are fed with a carefully controlled mixture of iron ore, coke and limestone. To evaluate the durability studies of m20 and m40 grade ggbs replacement concrete, with 1% and. Properties of concrete with ground granulated blast. Ground granulated blast furnace slag ggbs is a byproduct from the blastfurnaces used to make iron. Yasutaka sagawa, daisuke yamamoto and yoshikazu henzan, properties of concrete with ggbs and its applications for bridge superstructures, third international conference on sustainable construction materials and. Due to the more steady hydration of concrete made with ggbs, heat is released in a more controlled manner. Sometimes described as severe andor excessive, it appears the cracks occurred even when specifications were strictly followed and the concrete designed, supplied, placed, and cured in accordance with formal standards and good. Concrete cubes of 0%, 30%, 40% and 50% of ggbs concrete of m20 and m40 grade concrete exposed to h 2 so 4 and hcl of 1% and 5% concentrations are tested for co mpressive strength. Ground granulated blast furnace slag in concrete and its. Investigating a new method to assess the selfhealing performance.
Granulated blast furnace slag is obtained by rapidly chilling quenching the molten ash from the furnace with the help of water. Shrinkage cracking resistance of blast furnace slag blended cement. Repairing cracked and crumbling gypcrete floors hunker. Thermal cracking can be especially problematic in mass concrete pours which create large amounts of heat. For example, partial replacement of portland cement by ggbs generally increases the resistance of concrete to sulphate attack and chloride attack. What is maximum content of ggbs in concrete mix design. What is the advantage of using ggbs as replacement of. Concrete grades of m 25 have been taken for the work. However, it was found that concrete made with blends of 35%, 50% and 65% ggbs performed much better.
Early age behaviour and cracking risk of concretes containing ggbs. First the influence of mineral additives such as fly ash fa and blast furnace slag. The study results showed that, with the increase in percentage of ggbs, the. Properties of concrete containing ground granulated blast. Concrete made with ggbs cement sets more slowly than concrete made with ordinary portland cement, depending on the amount of ggbs in the cement mix, but also continues to gain strength over a longer period leading to improved overall durability and life expectancy. Pdf the effects of temperature on the cracking risk of normal strength concretes.
In rarer instances thermal cracking can occur when concrete surfaces are exposed to extreme temperature rapidly. The problem of durability does not occur when the crack width is 0. It improves the quality and durability of concrete. In most cases thermal cracking occurs at early ages. Pdf effect of temperature on the cracking risk of concretes. Enhanced autogenous healing of ground granulated blast furnace. The most important effects of elevated temperature on concrete are. As ggbs is partially replaced with the cement, the consumption of the cement is reduced and also the cost of construction is reduced. To circumvent this problem, we used the artificial crack method employed by.
Because concrete made with ggbs goes through a 2stage hydration process the initial reaction is slowers. Groundgranulated blast furnace slag is highly cementitious and high in csh calcium silicate hydrates which is a strength enhancing. Earlyage strength of ggbs concrete is lower than the normal pc concrete which limits its use in the fasttrack. Influence of ggbs on durability and corrosion behavior of.
Apart from the consideration of longterm durability, the use of pfa and ggbs results in the reduction of heat of hydration so that the problem of thermal cracking is greatly reduced. Cracking is a common problem in concrete structures in reallife. Lower early age temperature rise, reducing the risk of thermal cracking in large pours. Hydrating cement generates heat due to exothermic reaction and this heat causes the concrete to expand, and then contract when cooling. As a result, the inclusion of ggbs was demonstrated to form a selfhealing material. On its own ggbs hardens slowly and, for use in concrete, it needs to be activated by combining it with an activator typically portland cement cem i but alkali activation is also used. A typical combination is 50% ggbs with 50% cem i, but percentages of ggbs anywhere between 20 and 80%. Concrete slabs can shrink as much as 12 inch per 100 feet. This paper presents the workability study of concrete with ggbs as a replacement material for cement without the addition of super plasticizer.
The topic deals with the usage of ggbs and advantages as well as disadvantages in using it in concrete. Therefore, crack repair is necessary for improving the durability of concrete. Ggbs is used as a partial replacement for ordinary cement in concrete. The concrete with 100% opc degraded to powder over the following year, while the concrete made with ggbs maintained its strength over the same period.
The wetter or soupier the concrete mix, the greater the shrinkage will be. The ground granulated blast furnace slag ggbfs is a byproduct of iron manufacturing which when added to concrete improves its properties such as workability, strength and durability. The present paper is an effort to quantify the strength of ground granulated blast furnace slag ggbs at various replacement levels and evaluate its efficiencies in concrete. Approximately 2 000 000 tonnes of ggbs produced in uk 2,000,000 2008. Concrete so reinforced is called fiber reinforced concrete frc. Fast patch concrete repair simply mix with water and trowel. Remove the excess product by scraping a flatsided trowel across the surface. Cracking risk of concrete structures in the hardening phase core. During this process ggbs is added into it as per % and grinded with clinker and gypsum.