본 연구에서는 화산재를 건설재료로 활용하기 위하여 백두산, 한라산의 화산재 및 다공성의 제올라이트에 시멘트 및 메타카올린을 첨가한 공시체에 대한 재령 0일, 7일, 28일 배합비별 압축강도 특성 데이터를 바탕으로 인공신경망 모델에 적용하여 학습, 예측함으로써 강도예측을 위한 인공신경망의 적용 가능성을 평가하였다. 인공신경망 모델에는 역전파 학습알고리즘(back-propagation learning algorithm)이 적용되었으며, 다양한 입력변수를 달리한 최적의 인공신경망 조건에서 학습을 시행하였다. 또한, 다양한 배합조건이 일축압축강도에 미치는 영향에 대한 민감도 분석을 실시하였다. 이러한 연구를 통해 얻어진 결과물은 화산재를 활용한 블록의 일축압축강도 특성을 파악하는데 좋은 툴이 될 것으로 기대된다.

In this study, compressive capacity of a new form-block-wall (FBW) was studied through both the prism test and compressive strength test for single form-block. In the experiment, main variables are the difference in mix design of block and in strength of grout concrete. The result of prism test showed that the compressive strength of FBW was largely influenced by the strength of grout concrete while it was not influenced by the block‘s mix design difference.

Based on the study of compressive strength due to SPC(sulfur polymer cement) content variation in the sulfur polymer concrete , it was found that the SPC content was required more than 16% to get over 50 MPa compressive strength and increasing ratio of the strength was greatest at SPC 14%.

The objective of this study is to investigated the compressive characteristics properties used cement paste containing Silica Fume Binder with elapsed curing time.

The objective of this study is to investigated the compressive characteristics properties used cement paste containing 30% blast furnace slag with curing days.

The objective of this study is to investigated the compressive characteristics properties used cement paste containing 20% fly ash with curing days.

In case of measuring strength of concrete using ultrasonic pulse testing, setting reasonable range of limitations to get reliable strength data results is highly recommended. To resolve this issue, ultrasonic testings were performed on several concrete specimens ,randomly selected and contain strength ranged from 20 to 200MPa, to measure values of ultra sonic velocity and actual strength. Then advanced data analyses were performed based on the results from the experimental works.

This paper reviewed on the minimum strength of concrete in cold climates from the viewpoint of durability. The results show that the minimum strength to prevent early frost damage recommend to 21 MPa.

In this study, to improve the early-age compressive strength of concrete, the powder of rapid setting additives crushed by treatment with functional grinding aid, the power-typed rapid setting cement clinker by sintering industrial waste and byproducts containing a large amount of CaO-SiO2-Al2O3 was developed. And, after adding smart BFS powder to powder of rapid setting additives, the strength tests were performed

Greenhouse gas emissions, ranking the world's top 10 ranked Korea in the development of the related technologies and the relevant laws and the formulation of plans in 2008 to a low-carbon, green growth a new vision of national growth is accelerating. In addition, Cement substitute material developed using high-performance concrete cement reduction technology, carbon capture technology is being studied. Therefore, in this study, utilizing activated industrial byproducts carbon Absorbing for road materials developed as part of the study typical industrial byproducts, Blast Furnace Slag and calcium hydroxide, sodium silicate mortar on Fundamental Properties of experiments the flow experiments, the compressive strength experiments performed basic experiments with respect to the results obtained were investigated

In this study, KS F 2405 was used to investigated the compressive strength of property of high performance concrete (HPC) using the fly ash and silica fume. The experiments were carried out silica fume-binder ratio from 5% (SF5) and fly ash 25%+silica fume 5% (FA25SF5). The compressive strength of HPC determined on 7days and 28days.

To the goal of improving the early compressive strength of the mortar including Ground granulated blast furnace slag under low-temperature environment, Industrial byproducts including SiO2 and Al2O3 was fired and than 7% of it was added into Ground granulated blast furnace slag. By checking compressive strength and activity index from different mixing rate, in spite of low strength development than OPC 100%, when using firing powder, the expectation of increasing strength by curing time was affirmative

In this study, we investigated the physical properties and thermal behaviors of specimens that applied different mixing ratios of foaming agent to evaluate the possibility of use in the structural elements. We proposed the estimating equation for compressive strength of each mix having different ratio of foaming agent. We also confirmed that the density of cement matrix is decreased as the mixing amount of foaming agent increase up to 0.6% of foaming agent mixing ratio which was observed by SEM. Based on porosity and compressive strength of control mortar without foaming agent, we built the estimating equations of compressive strength for mortars with foaming agent

Up to date, the specifications of construction and maintenance for airport pavement are primarily from ICAO (International Civil Aviation Organization), IATA (International Air Transport Association) or FAA (Federal Aviation Administration). In order to consider circumstances such as rainfall characteristics, this study aims to develop pervious concrete for base course of an airport pavement. Strength characteristic of pervious concrete was investigated with respect to different maximum course aggregate size. When 25mm sized aggregate was used, greatest strength was achieved.

In this study, one of nondestructive evaluation (NDE)　techniques for the effective maintenance of underwater concrete structures are investigated: Ultrasonic Pulse Velocity Method and Rebound hardness Test. Currently, lots of ROV(Romotely Operated Vehicle) Systems to inspection Underwater Concrete Structures are being considered.

In this study, I tried to derive the expression intensity estimation through analyzing the correlation between wave velocity and compressive strength of high-strength concrete and normal-strength one, using ultrasonic pulse velocity which is one of the non-destructive tests which do not damage the structure. By producing a material age strength and body separate experiment which is applied to the ultrasonic pulse velocity, we have derived the estimating compressive strength such as a formula strength of normal-strength concrete : Fc=0.0841vp3.6018, R2=0.82 high strength concrete : Fc=0.0008vp6.9287, R2=0.88. As a result of this verification experiment, the estimated error rate of the compressive strength of normal strength concrete is 16.32%, in the case of high-strength concrete is now 7.58 percent.

본 연구에서는 CaO-SiO2-Al2O3가 다량 함유된 산업폐기물과 산업부산물을 소성하여 개발한 분말형 속경성 분말을 초기강도의 향상을 위해 기능성 분쇄조제로 처리하여 분쇄한 속경성 미분말을 제조하였다. 이렇게 제조된 미분말을 BFS 분말과 일정비율로 혼합한 후, 시멘트에 첨가하여 모르타르 압축강도 실험을 실시하였다. 그 결과 BFS 조기강도 향상 실험 (Series I)에서는 클링커 분쇄시 기능성 분쇄조제가 첨가되어 분쇄된 속경재가 혼합된 BFS의 초기강도 발현이 우수하며 OPC 조기강도 향상 실험 (Series II)에서는 Clinker-C에 본 실험의 기능성 분쇄조제가 첨가되어 분쇄된 속경성의 분말형 자극제가 첨가된 경우에 가장 압축강도가 높은 사실을 알 수 있었다.

콘크리트의 강도는 시간에 따라 증가하며, 많은 연구에서 시간에 대한 회귀 분석식을 사용하고 있다. 본 연구는 수화물량을 수화도 및 공극률의 함수로 가정하였으며, 재령의 증가에 따라 감소하는 공극률을 이용하여 고성능 콘크리트의 압축강도 모델링을 수행하였다. 본 연구에서는 기존의 시간에 대한 회귀분석없이 공극률의 감소만을 이용하여 압축강도를 예측하였다. 총 21개의 고성능 콘크리트 배합에 대해 초기재령 콘크리트의 거동 해석프로그램인 DUCOM을 이용하여 각각의 공극률을 도출하였으며, 강도 모델링을 수행하였다. OPC 콘크리트에 대해서 수화도, 단위시멘트량, 공극률의 함수로 강도 예측식을 제안하였으며, GGBFS 및 FA를 혼입한 콘크리트에 대해서는 장기강도 영향을 구현하기 위해 공극률을 고려한 장기강도변수를 도입하였다. 기존의 실험결과와의 비교를 통하여 제안된 강도예측식의 타당성을 입증하였다.

Temperature of fresh concrete can be effectively used to predict the strength of concrete being cured and make an informed decision for stripping the molds. A hygrothermograph and thermo-couple sensors that require an extensive wiring have been applied to measure a temperature of concrete at the early stage of the curing process on site. Therefor, this study on the strength prediction using Maturity is mainly focused on, but the study on the concrete mixing blast furnace slag powder is insufficient. The purpose of this study is to investigate the relationships between compressive strength and equivalent age by Maturity function and is to compare and examine the strength prediction of concrete mixing Blast Furnace Slag Power using ACI and Logistic Curve prediction equation.

As Concrete is construction materials which is unevenly mixed with cement, aggregate and water, compressive strength and modulus of elasticity is an important factor to seize movement of structures. The purpose of this study is to investigate a correlation compressive strength and modulus of elasticity according to the size of structures, and also to analyze and compare to prediction equation of many countries.