Volume Ground Granulated Blast Furnace Slag Research Articles

Effect of Ground Granulated Blast-Furnace Slag on the Bond Strength of Recycled Aggregate Concrete

This research experimentally investigated the bond strength of recycled aggregate concrete containing high volume ground granulated blast-furnace slag (GGBFS). Concrete mixtures made with 0%, 15%, 45% and 75% replacement of cement with GGBFS were prepared. Water-to-binder ratios ranged from 0.30 to 0.50. The fresh properties, compressive strength and pullout bond strength of concrete were measured and presented. Test results shows that the compressive strength and bond strength of concrete containing GGBFS were superior to the concrete without GGBFS at all ages. In addition, the bond strength of the recycled aggregate concrete containing high volume GGBFS (75% cement replacement) could exceed that of natural aggregate concrete without GGBFS. This result shows that it is feasible for applying recycled aggregate concrete incorporating high volume GGBFS in concrete constructions.

Predicting compressive strength of high-performance concrete with high volume ground granulated blast-furnace slag replacement using boosting machine learning algorithms

Predicting the compressive strength of concrete is a complicated process due to the heterogeneous mixture of concrete and high variable materials. Researchers have predicted the compressive strength of concrete for various mixes using machine learning and deep learning models. In this research, compressive strength of high-performance concrete with high volume ground granulated blast-furnace slag replacement is predicted using boosting machine learning (BML) algorithms, namely, Light Gradient Boosting Machine, CatBoost Regressor, Gradient Boosting Regressor (GBR), Adaboost Regressor, and Extreme Gradient Boosting. In these studies, the BML model’s performance is evaluated based on prediction accuracy and prediction error rates, i.e., R2, MSE, RMSE, MAE, RMSLE, and MAPE. Additionally, the BML models were further optimised with Random Search algorithms and compared to BML models with default hyperparameters. Comparing all 5 BML models, the GBR model shows the highest prediction accuracy with R2 of 0.96 and lowest model error with MAE and RMSE of 2.73 and 3.40, respectively for test dataset. In conclusion, the GBR model are the best performing BML for predicting the compressive strength of concrete with the highest prediction accuracy, and lowest modelling error.

Mercury intrusion porosimetry characterization of micropore structures of high-strength cement pastes incorporating high volume ground granulated blast-furnace slag

In this study, we characterized the micropore structures of high-strength cement pastes incorporating high volume ground granulated blast-furnace slag (GGBFS). Using mercury intrusion porosimetry, we measured the pore-size distributions of cement pastes with different GGBFS replacement ratios at ages of 3, 7, 28, and 91d. The test results indicated that the total porosity increased with increasing GGBFS ratio in the specimens at early ages, whereas it decreased at later ages. The replacement ratio of 65% produced the densest pore structure, which was consistent with compressive strength test results.

Sulfate resistance of plain and blended cement

Abstract This paper presents a laboratory study on the sulfate resistance of blended cement combination of reference Portland cement with high volume ground granulated blast-furnace slag (GGBS) and natural pozzolan (NP). The exposure solutions were tap water containing 5% magnesium sulfate solution and 5% sodium sulfate solution. Two types of grinding method (separately grinding and intergrinding, two finenesses (250 m 2 /kg and 500 m 2 /kg) and three different proportions (10%, 20%, and 30% by weight of mixture)) of each of two different additives (GGBS and NP) in equal amounts were employed. In addition to these blends, plain Portland cements without additives were prepared as references specimens. Standard Rilem sample size (40 mm × 40 mm × 160 mm) was used for the experimental study. It was observed that the sulfate resistances of blended cements were significantly higher both against sodium sulfate and magnesium sulfate attacks than references cement. Final strength reductions for finer mixes attacked by magnesium sulfate were marginally lower than those attacked by sodium sulfate. On the other hand, no particular relation was found between the sulfate resistance of the mortars and the grinding methods.