Study of brazilian structural concrete block conformity

This paper presents a study of the conformity of structural concrete blocks manufactured and used in masonry construction in Brazil. It is based on compressive strength tests, on dimensional analysis and absorption tests of over six thousand samples from three classes (A, B and C) and two modular sizes (M-15 and M-20). National results show that blocks tend to have an estimated compressive strength higher than specified, except blocks from class A. Regional results show that blocks manufactured in the northeast (NE) are consistently non-conforming, for all block classes. The study also shows that dimensional variations and absorption tests results are within code tolerances.

Keywords:
structural concrete blocks; structural masonry; structural safety

Authorship

W. C. SANTIAGO

Colegiado de Engenharia Civil, Universidade Federal do Vale do São Francisco, UNIVASF, Juazeiro, BA, Brasil; wagner.santiago@univasf.edu.brUniversidade Federal do Vale do São FranciscoBrazilJuazeiro, BA, BrazilColegiado de Engenharia Civil, Universidade Federal do Vale do São Francisco, UNIVASF, Juazeiro, BA, Brasil; wagner.santiago@univasf.edu.br

A. T. BECK

Departamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, USP, São Carlos, SP, Brasil. atbeck@sc.usp.brUSPBrazilSão Carlos, SP, BrazilDepartamento de Engenharia de Estruturas, Escola de Engenharia de São Carlos, USP, São Carlos, SP, Brasil. atbeck@sc.usp.br

SCIMAGO INSTITUTIONS RANKINGS

Figures | Tables

Figures (5)
Tables (8)

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Figure 1
Ratios between estimated and specified characteristic strength (f_bkest/f_bck) by modular sizes

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Figure 2
Ratio between average and specified characteristic strength (f_bm/f_bck) by modular sizes

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Figure 3
The coefficient of variation (C.V.) of compressive strength by modular sizes

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Figure 4
The average absorption (A_bm) by modular sizes

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Figure 5
The coefficient of variation (C.V.) for absorption by modular sizes

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Table 1
Quantification of the specimens by Brazilian region

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Table 2
Quantification of the specimens by classes

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Table 3
Quantification of the specimens by modular sizes

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Table 4
Compressive strength results by brazilian regions

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Table 5
Dimensional analysis results by brazilian regions

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Table 6
Thickness results by brazilian regions

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Table 7
Gross area results by brazilian regions

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Table 8
Absorption analysis results by Brazilian regions

Figure 1 Ratios between estimated and specified characteristic strength (f_bkest/f_bck) by modular sizes

Figure 2 Ratio between average and specified characteristic strength (f_bm/f_bck) by modular sizes

Figure 3 The coefficient of variation (C.V.) of compressive strength by modular sizes

Figure 4 The average absorption (A_bm) by modular sizes

Figure 5 The coefficient of variation (C.V.) for absorption by modular sizes

Table 1 Quantification of the specimens by Brazilian region

Test	Region	Quantity	Percentage
f_b, L, C, H, E and A	S	433	8
	SE	2948	55
	NE	2005	37
	Total	5386	100
A_b	S	81	8
	SE	447	41
	NE	560	51
	Total	1088	100

Table 2 Quantification of the specimens by classes

Test	Class	Quantity	Percentage
f_b, L, C, H, E and A	A	1044	20
	B	1740	32
	C	2602	48
	Total	5386	100
A_b	A	255	23
	B	570	52
	C	263	25
	Total	1088	100

Table 3 Quantification of the specimens by modular sizes

Test	Modular size	Quantity	Percentage
f_b, L, C, H, E and A	M-15	3718	69
	M-20	1668	31
	Total	5386	100
A_b	M-15	387	36
	M-20	701	64
	Total	1088	100

Table 4 Compressive strength results by brazilian regions

Class	Modular size	Region	f_bkest / f_bk	f_bm / f_bk	C.V.
A	M-15	S	0,909	1,226	0,220
		SE	0,940	1,447	0,260
		NE	0,743	1,239	0,190
		BR	0,860	1,358	0,239
	M-20	S	-	-	-
		SE	1,065	1,470	0,185
		NE	0,818	1,239	0,219
		BR	0,900	1,364	0,197
Class	Modular size	Region	f_bkest / f_bk	f_bm / f_bk	C.V.
B	M-15	S	1,085	1,727	0,261
		SE	1,153	1,723	0,270
		NE	0,878	1,357	0,281
		BR	0,990	1,592	0,279
	M-20	S	-	-	-
		SE	1,163	1,598	0,302
		NE	0,839	1,202	0,222
		BR	1,023	1,328	0,248
Class	Modular size	Region	f_bkest / f_bk	f_bm / f_bk	C.V.
C	M-15	S	0,903	1,678	0,360
		SE	1,449	1,738	0,230
		NE	0,765	1,259	0,393
		BR	1,150	1,566	0,294
	M-20	S	-	-	-
		SE	1,556	1,684	0,144
		NE	0,728	1,040	0,331
		BR	1,215	1,419	0,221

Table 5 Dimensional analysis results by brazilian regions

Class	Modular size	Region	W_m / W_nom	σ_L (mm)	L_m / L_nom	σ_C (mm)	H_m / H_nom	σ_H (mm)
A	M-15	S	1,002	0,75	1,002	1,73	1,000	1,58
		SE	1,002	0,60	1,001	1,43	1,001	1,04
		NE	1,004	0,83	1,003	1,08	1,003	0,92
		BR	1,003	0,66	1,001	1,40	1,001	1,06
	M-20	S	-	-	-	-	-	-
		SE	1,000	0,36	1,000	0,52	0,998	0,57
		NE	1,005	0,83	1,004	1,13	1,005	0,93
		BR	1,002	0,53	1,001	0,73	1,001	0,71
Class	Modular size	Region	W_m / W_nom	σ_L (mm)	L_m / L_nom	σ_C (mm)	H_m / H_nom	σ_H (mm)
B	M-15	S	1,017	8,24	1,004	2,51	0,990	3,31
		SE	1,000	5,21	1,001	0,70	1,000	0,96
		NE	1,004	0,86	1,003	1,13	1,003	1,10
		BR	1,003	3,57	1,002	0,94	1,001	1,10
	M-20	S	-	-	-	-	-	-
		SE	1,001	0,52	1,000	0,77	1,000	0,70
		NE	1,002	2,62	1,003	1,09	1,004	1,11
		BR	1,002	1,96	1,002	0,99	1,002	0,98
Class	Modular size	Region	W_m / W_nom	σ_L (mm)	L_m / L_nom	σ_C (mm)	H_m / H_nom	σ_H (mm)
C	M-15	S	1,011	1,25	1,006	8,37	0,990	2,81
		SE	1,001	0,40	1,000	0,52	1,000	0,83
		NE	1,010	7,89	1,001	0,53	1,001	1,12
		BR	1,005	2,92	1,001	1,27	0,999	1,11
	M-20	S	1,002	1,08	1,003	0,85	0,998	1,27
		SE	1,000	0,41	1,000	0,29	0,999	0,46
		NE	1,002	0,53	1,001	0,58	1,001	0,77
		BR	1,001	0,48	1,001	0,42	1,000	0,60

Table 6 Thickness results by brazilian regions

Class	Modular size	Region	T_m / T_nom	C.V.	% nonconforming samples
A	M-15	S	-	-	-
		SE	1,065	0,031	1
		NE	-	-	-
		BR	1,065	0,031	1
	M-20	S	-	-	-
		SE	1,187	0,118	0
		NE	-	-	-
		BR	1,187	0,118	0
Class	Modular size	Region	T_m / T_nom	C.V.	% nonconforming samples
A	M-15	S	-	-	-
		SE	1,062	0,030	3
		NE	1,030	0,037	2
		BR	1,058	0,031	2
	M-20	S	-	-	-
		SE	1,147	0,127	0
		NE	1,062	0,021	0
		BR	1,092	0,059	0
Class	Modular size	Region	T_m / T_nom	C.V.	% nonconforming samples
A	M-15	S	-	-	-
		SE	1,142	0,075	0
		NE	1,339	0,071	0
		BR	1,269	0,072	0
	M-20	S	1,216	0,041	0
		SE	1,194	0,101	0
		NE	1,369	0,055	0
		BR	1,336	0,062	0

Table 7 Gross area results by brazilian regions

Class	Modular size	Region	A_m / A_nom	C.V.
A	M-15	S	1,009	0,008
		SE	1,003	0,005
		NE	1,007	0,007
		BR	1,004	0,006
	M-20	S	-	-
		SE	1,000	0,002
		NE	1,010	0,006
		BR	1,004	0,003
Class	Modular size	Region	A_m / A_nom	C.V.
B	M-15	S	1,013	0,017
		SE	1,003	0,005
		NE	1,008	0,008
		BR	1,006	0,007
	M-20	S	-	-
		SE	1,001	0,003
		NE	1,008	0,006
		BR	1,005	0,005
Class	Modular size	Region	A_m / A_nom	C.V.
C	M-15	S	1,012	0,073
		SE	1,000	0,031
		NE	-	-
		BR	1,002	0,038
	M-20	S	1,004	0,006
		SE	1,000	0,002
		NE	-	-
		BR	1,000	0,003

Table 8 Absorption analysis results by Brazilian regions

Class	Modular size	Region	A_bm (%)	C.V.	% nonconforming samples
A	M-15	S	-	-	-
		SE	5,10	0,281	3
		NE	4,52	0,283	1
		BR	4,96	0,282	2
	M-20	S	-	-	-
		SE	6,33	0,194	6
		NE	5,02	0,376	5
		BR	5,46	0,315	4
Class	Modular size	Region	A_bm (%)	C.V.	% nonconforming samples
B	M-15	S	-	-	-
		SE	7,05	0,166	2
		NE	4,72	0,249	0
		BR	4,96	0,281	1
	M-20	S	6,68	0,101	0
		SE	7,01	0,196	2
		NE	4,81	0,296	0
		BR	5,37	0,255	0,5
Class	Modular size	Region	A_bm (%)	C.V.	% nonconforming samples
C	M-15	S	-	-	-
		SE	7,59	0,160	0
		NE	-	-	-
		BR	7,59	0,160	0
	M-20	S	9,56	0,100	0
		SE	6,97	0,132	0
		NE	4,15	0,227	0
		BR	5,82	0,173	0

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Study of brazilian structural concrete block conformity

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